From: Duncan Wood on
On Thu, 25 Mar 2010 00:35:41 -0000, Rob <mesamine(a)gmail.com> wrote:

> On 24/03/2010 7:42 PM, Mrcheerful wrote:
>> Adrian wrote:
>>> Rob<mesamine(a)gmail.com> gurgled happily, sounding much like they were
>>> saying:
>>>
>>>>> Indeed. I also doubt that a vehicle with an egr has a carb...
>>>
>>>> Why? genuine question.
>>>
>>> Simply because fuel injection is an easier way to emissions benefits,
>>> and started to become damn near ubiquitous before EGR started to be
>>> particularly common.
>>>
>>> It's not impossible - my Saab has EGR, whilst 'erselfs 205 is the same
>>> age and has a carb - but I just can't quite see it.
>>
>> in this case (the C3) it is very unlikely as it seems it is a diesel.
>>
>>
>
> That's why I asked as it may be confusing as to what is being referred
> to as EGR.
>
> EGR was some of the first bit of pollution gear fitted and it was to
> recycle the exhaust gas so more exhaust fuel had a second burn to reduce
> the emissions.
>
> When injection engines came along the fuel being metered better reduced
> the pollution with a more even and complete burn.
>
> Turbo engines operate differently again.
>
> There was a lot of unburned fuel down the exhaust when fuel was cheap.
> Pre mid 70's era.
>
> Its been the development quite a few years now to comply with pollution
> regulations.
>
> Could be wrong!
>
> r


Yup, it's to reduce the formation of NOx by reducing peak combustion
temperature, there's very little unburnt fuel in your exhaust.

--
Duncan Wood
From: Adrian on
Rob <mesamine(a)gmail.com> gurgled happily, sounding much like they were
saying:

> That's why I asked as it may be confusing as to what is being referred
> to as EGR.
>
> EGR was some of the first bit of pollution gear fitted and it was to
> recycle the exhaust gas so more exhaust fuel had a second burn to reduce
> the emissions.
>
> When injection engines came along the fuel being metered better reduced
> the pollution with a more even and complete burn.
>
> Turbo engines operate differently again.
>
> There was a lot of unburned fuel down the exhaust when fuel was cheap.
> Pre mid 70's era.
>
> Its been the development quite a few years now to comply with pollution
> regulations.
>
> Could be wrong!

Umm, the engine I have with EGR is an injected turbo.

EGR valves are notoriously troublesome on several recent common-rail
turbo diesel engines.