Thread: EGR

Eu3 EGR is more restrictive as it has a throttle valve also.

Removing it is even more beneficial on the D2a (Eu3) engines.

No need to remove the cooler, just fit the extra plates at either end.

In effect yes. I used to hate the EGR as well, but work on my DME thesis has led to a lot of reading into diesel emissions and the EGR system as well.

This is taken from a literature review on EGRs:
The EGR reduces NOx, by decreasing the peak temperature in the diesel combustion flame. It creates a dilution effect that describes the flame temperature and NOx emission reductions resulting solely from a reduction in oxygen mass fraction resulting from the displacement of some of the oxygen in the fresh intake air charge by an inert gas. The dilution effect is the most significant contributor to the NOx reduction achievable with EGR [Hawley 1998][Mellow 1999]. The impact of the dilution effect is primarily through a reduction in the local flame temperature from a broadening of the flame due to the reduction in the oxygen molar fraction. An increased proportion of non-oxygen molecules in the broadened flame zone absorb heat from the flame and lowers the temperature.

Originally Posted by Hendrik

In effect yes. I used to hate the EGR as well, but work on my DME thesis has led to a lot of reading into diesel emissions and the EGR system as well.

This is taken from a literature review on EGRs:
The EGR reduces NOx, by decreasing the peak temperature in the diesel combustion flame. It creates a dilution effect that describes the flame temperature and NOx emission reductions resulting solely from a reduction in oxygen mass fraction resulting from the displacement of some of the oxygen in the fresh intake air charge by an inert gas. The dilution effect is the most significant contributor to the NOx reduction achievable with EGR [Hawley 1998][Mellow 1999]. The impact of the dilution effect is primarily through a reduction in the local flame temperature from a broadening of the flame due to the reduction in the oxygen molar fraction. An increased proportion of non-oxygen molecules in the broadened flame zone absorb heat from the flame and lowers the temperature.

Well I anticipate this will really get the boys going.

My armchair understanding is that for compliance in Australia is done on particulate material not NOx gas emissions? Is lowering the combustion temp by the introduction of non combustible gas (NOx) a benefit?

Ive read that with the EGR closed some people are getting considerable gains in fuel efficiency.

If these fuel efficiency gains are weighed against the environmental benefits of having an EGR which would win?

Put simply, which is greener? Having an EGR or using a less fuel?

Originally Posted by Tombie

Eu3 EGR is more restrictive as it has a throttle valve also.

Removing it is even more beneficial on the D2a (Eu3) engines.

No need to remove the cooler, just fit the extra plates at either end.

why the need to close up the cooler once disconnected? other than to keep it clean for future reconnection...

Originally Posted by jwb

why the need to close up the cooler once disconnected? other than to keep it clean for future reconnection...

none really,

i run mine with it open