Decat and EGR bypass advice please.

[DerekS]

Originally Posted by HarryM1BYT

I can't get my head around it, the EGR cooling the engine at all - how does that work then?

Harry .. Please read the many posts here where this effect is explained.

But just in case, I repeat here :>>>>

When exhaust gases are introduced into the cylinder, the combustion temperature is reduced, due to there being more CO2 and less O2. This results in less NOx nasties being produced. And that is the reason for the exhaust gas recirculation.

A second effect of the lower combustion temperature could be a lower engine temperature, but this is a secondary effect, and not the main reason for EGR. (But surely engine temp is controlled by the water jacket and pump, after all its not aircooled is it )


I agree with the Mod, who said this is an interesting thread and so didnt close it .

But to all posters, as M.Winner and a.n.other recently said " calm down , calm down ".

[ceedy]

Not been about on here for sometime but come back and still find Poor old Chrissyboy getting lots of stick .. again..

Mind you he does ask for it a lot by posting often non factual info , ( sounding usually like he's just repeating info he's got from some other closet expert) .

Never mind ..its what makes life on here entertaining !

But on topic .. EGRs Bypass's are OK , work well are better for the engine and Don't cause any problems at all !! ... So there!

And thats final !


Chris

[James.uk]

My ZX 1.9 diesel has no EGR or cat.. But it is obviously unaware of that fact so runs nicely anyway..
...

[soapy]

Them good old zx diesels wil even run happily on chip fat James provided they have the bosch pump,nice smell too.

[HarryM1BYT]

Originally Posted by DerekS

Harry .. Please read the many posts here where this effect is explained.

But just in case, I repeat here :>>>>

When exhaust gases are introduced into the cylinder, the combustion temperature is reduced, due to there being more CO2 and less O2. This results in less NOx nasties being produced. And that is the reason for the exhaust gas recirculation.

A second effect of the lower combustion temperature could be a lower engine temperature, but this is a secondary effect, and not the main reason for EGR. (But surely engine temp is controlled by the water jacket and pump, after all its not aircooled is it )


I agree with the Mod, who said this is an interesting thread and so didnt close it .

But to all posters, as M.Winner and a.n.other recently said " calm down , calm down ".

Thanks for that. So if I understand the combustion part of the process correctly, it means a less complete combustion, a cooler combustion and more fuel used to over come the poorer efficiency when the EGR valve opens - is that about right?

[DerekS]

Originally Posted by HarryM1BYT

Thanks for that. So if I understand the combustion part of the process correctly, it means a less complete combustion, a cooler combustion and more fuel used to over come the poorer efficiency when the EGR valve opens - is that about right?

Not neccessarily less complete, but a slower rate cos the oxygen is not in as great an excess, and so a cooler rate. It is still complete combustion though, (no permanent smoke) so efficiency should not be any different.

Remember that the amount of gas recirculated is calculated by the designer, and controlled by the EGR valve system, so that the fuel mixture will probably never get too rich ( for diesel engines ).

Thinking about this further, Diesel engines always run lean, there is no throttle to restrict the intake air. The EGR valve can be regarded as a throttle that restricts the oxygen supply.
Of course all these arguments refer to a steady state, things will be different when the pedal hits the metal suddenly.