Basic explanation of the CDI intake system

[leicschris]

Hi All

I am still trying to get to grips with the diesel engine, with all of my previous experience being with petrol engines.


I was looking at the engine today starting the planning for cleaning out the EGR system and am a bit confused.

On the drivers side of the engine is what I guess hold the Air Filter, and on this casing is a display window with red inside it, and a knob to adjust. My red segment is between the 75% and the 100%. What does this mean, and what should it be at.

At the front of this air box is what looks like an air flow meter, and the feed pipe to it. The feed pipe seems to coming from the turbo unit below it. A fresh air pipe comes from a hole beside the radiator and goes behind the airflow meter?

Am I following this right, I always assumed on petrols that air flow meter measures the fresh air coming into the engine, but this CDI looks different.

Also, where is the EGR system in relation to this that needs to be stripped and cleaned.

Sorry for my ignorance

Thanks

Chris

 

[jay1983]

Your egr valve is usually located on the opposite side of the engine. On the inlet side

 

[leicschris]

I haven't seen any inlet parts on the other side with the exception of the fuel rail

I could be wrong but it looks like both inlet and outlet are on top of each other on the cdi Diesel engine

Chris

 

[renault12ts]

The % reading on the air filter is advising how clogged the filter is. In the red zone...may need changing.

 

[renault12ts]

I haven't seen any inlet parts on the other side with the exception of the fuel rail

I could be wrong but it looks like both inlet and outlet are on top of each other on the cdi Diesel engine

Chris

The exhaust manifold is under the air filter. The inlet manifold, with the egr, is on the other side of the engine.

Air enters the filter and is then compressed by the turbo...this is fed via a large intercooler to the inlet manifold.

 

[leicschris]

Ah that makes sense

I will remove the engine covers again and have a good look at the inlet side

Thanks

Chris

 

[jay1983]

Is this your engine?

 

[leicschris]

Yes that's my engine

 

[grober]

OM648?

HERE YOU GO

Engine CDI_°Ù¶ÈÎÄ¿â

 

[leicschris]

Yep

that looks very similar to mine, except I have the older fuel filter that take the paper element inside a plastic case.

Where is the egr system?

thanks

Chris

 

[grober]

Did you click on the hypertext link I posted? Engine CDI_°Ù¶ÈÎÄ¿â
here's a pic from that CDI training course. You are looking for a metal connecting pipe from the exhaust manifold running round to the inlet manifold where the valve assembly will be. The small rectangular/cylindrical unit beside the red capped tube [ my engine pic] looks to be the EGR actuator altho the valve itself may be part of assembly below that. The plumbing on these engines is not easy to see with the engine in the car. Perhaps DM our resident diesel expert may wish to comment?

 

[grober]

Here's a video of a EGR valve on the later V6 diesel I imagine the EGR assembly is very similar.
[YOUTUBE HD]oy1eP_RwlNY[/YOUTUBE HD]

 

[leicschris]

Hi guys

thanks, that's very helpful

I didn't realize that was a link, i thought it was a title. have bookmarked it and will read and digest all of it, had a quick look and it looks a great resource.

would have saved it to my laptop but don't understand Chinese lol

thanks again

Chris