E320 Cdi Fuel Filter

[television]

How are these figures measured with an opacity meter?

These are not MOT test figures, they are manufacturers design figures and achievable by use of particulate filters, which incidentally are heated to high temperatures to burn off the trapped particulates.

Not correct at the present time, they cant be burnt off as the exhaust does not get hot enough on a diesel.

The new ideas in this field is to super heat the exhaust by using a late injection pulse. Super heating the exhaust gases is achieved by utilising a late injection pulse. The late injection ensures that the combustion is still taking place when the exhaust valve is open, thus combustion is still taking place in the exhaust system.
To reduce the particulates burning temperature an additive is required and could be in the form of a separate fuel tank, that adds "add blue" in a controlled amount
This is all waiting around the corner

 

[Dieselman]

Just thinking this through a bit more.

So lets assume the oil was fed through to the injectors neat and not diluted by diesel. This wouldn't happen but let's just assume for now.
Say the injectors couldn't atomise the oil so it stayed in droplet form and couldn't burn. What would happen to it?

It would either heat up and burn off or it would gradually run down the bores and into the sump where the rest of the engine oil resides.

Now if we are talking about incomplete combustion for a short while, well, that happens anyway on cold start and in particular if a glow plug fails.

Hard to see how that would be harmful.

I will change the filter as a test.. I'll report back..

 

[Dieselman]

This is all waiting around the corner

Other than on PSA cars already fitted with FAP and urea tank.

One mighty cloud of black smoke as they clear the FAP...

 

[television]

Just thinking this through a bit more.

So lets assume the oil was fed through to the injectors neat and not diluted by diesel. This wouldn't happen but let's just assume for now.
Say the injectors couldn't atomise the oil so it stayed in droplet form and couldn't burn. What would happen to it?

It would either heat up and burn off or it would gradually run down the bores and into the sump where the rest of the engine oil resides.

Now if we are talking about incomplete combustion for a short while, well, that happens anyway on cold start and in particular if a glow plug fails.

Hard to see how that would be harmful.

I will change the filter as a test.. I'll report back..

I find it great to have these conflabs, I learn a little more each day and am doing my best to understand diesels, so that I am ready for the first Diesel SL

 

[Dieselman]

I find it great to have these conflabs, I learn a little more each day and am doing my best to understand diesels, so that I am ready for the first Diesel SL

Merc were schedued to bring out a SL diesel about 5 years ago but market pressures stopped them doing so.
I mentioned this to one of my local Sales guys and he said 'There will never be an SL diesel'.

Hmm...
http://www.automobilemag.com/reviews/convertibles/0512_mercedes_benz_slk_sl_diesel/

There is one that a member had pictures of in the Paris dealership, along with a diesel SLK. Unfortunately the SL only gets the 4.0V8 twin turbo though.
I recently read a report that said by holding it on the brakes it was peeling the rubber off the rear tyres at 1000rpm...

Watch this space, if you reaad the SMMT report the sports segment is the only segment where diesel hasn't made big inroads, and there were no diesel sports cars available in 1997, but in 2006 a percentage of sports cars sold were diesels.

In Germany even many years ago the most popular Audi cabriolet was the TDi.

Your wish may soon be granted, having said that go for the Lightning car, apparently based on the SL platform.
http://www.lightningcarcompany.com/

EDIT:

Added SL linky..
http://www.ultimatecarpage.com/car/2243/Mercedes-Benz-Vision-SL-400-CDI.html

 

[television]

Merc were schedued to bring out a SL diesel about 5 years ago but market pressures stopped them doing so.
I mentioned this to one of my local Sales guys and he said 'There will never be an SL diesel'.

Hmm...
http://www.automobilemag.com/reviews/convertibles/0512_mercedes_benz_slk_sl_diesel/

There is one that a member had pictures of in the Paris dealership, along with a diesel SLK. Unfortunately the SL only gets the 4.0V8 twin turbo though.
I recently read a report that said by holding it on the brakes it was peeling the rubber off the rear tyres at 1000rpm...

Watch this space, if you reaad the SMMT report the sports segment is the only segment where diesel hasn't made big inroads, and there were no diesel sports cars available in 1997, but in 2006 a percentage of sports cars sold were diesels.

In Germany even many years ago the most popular Audi cabriolet was the TDi.

Your wish may soon be granted, having said that go for the Lightning car, apparently based on the SL platform.
http://www.lightningcarcompany.com/

EDIT:

Added SL linky..
http://www.ultimatecarpage.com/car/2243/Mercedes-Benz-Vision-SL-400-CDI.html

I remember the trolley buses when I was a lad, you could not stand when they took off.

There is no question about it, the torque on a diesel is just where you need it for average driving.

And as long as you know that I am on a learning curve with these things, I do say thanks on this forum that things stay polite, and nothing personal is ever intended. I am not the best one for mixing in groups as I have spent the best part of my life working alone. I have always envied those in a working group that can discuss a problem. Too late for me now

 

[Dieselman]

No issue for me television..

If you think diesels have torque try an electric powered vehicle. Full torque from zero to nearly maximum motor speed...for a given output a petrol engine has to have 3 times the power to achieve the same performance.

Just as an aside, you take a diesel car in for a filter change and the filter has to be primed.
Whare does the priming fuel come from given that the garage has no stock of fuel on site?

 

[c240yaz]

A lot of interesting reading above, but we will have to "agree" to disagree, on using engine oil to prime a diesel engine.

Regarding being sacked for incompetance, If I was in charge of a workshop, woe betide any mechanic I caught using engine oil in a customer's diesel fuel system. There is no reason or need to do this.

Maybe I would be tempted if I was "under fire" on the Basra road or something, and needed to get moving quickly..... lol.

If diesel cannot be drained from the existing system to prime the filter, I would not hesitate to go to the station and buy a gallon, rather than use engine oil.

No need to do a trial at the weekend on my behalf, I will take your word for it that it will work.

Dieselman, You have given me a lot of good advice in the past for my car maintenance, which I am grateful for, so please don't misinterperate this post and take it the wrong way..... !!

 

[Dieselman]

Too late, I'll have the filter later...

It's been running on Bio for about a year now so a change of filter might be a good thing as Bio cleans any old gum out of the fuel system so can clog the filter.

The only type of fuel pump that might bother me for this would be a common rail one, as they are ****(rather weak) but even then it's unlikely to harm it.

I'll let you know..

Cheers

 

[Dieselman]

they cant be burnt off as the exhaust does not get hot enough on a diesel.

Question: (proper, serious one)

Why doesn't the exhaust get as hot on a diesel as on a petrol engine?



Ooooo...I can feel the flames....

 

[c240yaz]

Question: (proper, serious one)

Why doesn't the exhaust get as hot on a diesel as on a petrol engine?



Ooooo...I can feel the flames....

Because Diesel ignition temp is lower in a compression ignition engine. If memory serves me correctly, around 210 degrees. Petrol ignition temp is higher, but cannot remember by how much.

(Long time since I got that lectured to me, or even thought about it).

 

[Dieselman]

Not sure about the actual ingition temperature, surely it must be the same as the compression temperature, which is about 400c, and under load a turbodiesel will have an EGT of about 700c so the actual cylinder flame temp must be that.

The answer is due to thermal efficiency. The diesel converts more of the energy stored in the fuel into motive power so there is less wastage of heat.

Some people don't like the word...Efficiency...

 

[c240yaz]

Not sure about the actual ingition temperature, surely it must be the same as the compression temperature, which is about 400c, and under load a turbodiesel will have an EGT of about 700c so the actual cylinder flame temp must be that.

The answer is due to thermal efficiency. The diesel converts more of the energy stored in the fuel into motive power so there is less wastage of heat.

Some people don't like the word...Efficiency...

You should have said that this was a test ! I would have done my homework first.

talking about work, I better get off this forum and get some done, or I will be getting laid off from this job for incompetency !!

 

[television]

Question: (proper, serious one)

Why doesn't the exhaust get as hot on a diesel as on a petrol engine?



Ooooo...I can feel the flames....

Cats on petrol run at 600c, diesels have a job to get up to 400c and its this that gives the soot problem. So surely this can only be down to the combustion of the fuel used. Its well known in fire brigade circles that they have to know what they are dealing with in chemical fires, there are huge differences in the temperatures of liquid and gases when ignited.
Thats the best that I can come up with.

 

[Dieselman]

They are different types of cats and do two different jobs. The cat is fueled by waste fuel from the engine of which there is less in a diesel.
Petrol cat is closed loop 3 way and diesel is open loop 2 way oxydisation cat.

I thought petrol cats made it upto 1000c.

 

[eurico]

Diesel EGT is lower because:
1) Fuel combustion heat is lesser 45<47 MJ/kg
2) Diesel always runs on excess air so at low/medium load there's the excess air that is absorbing combustion heat and does not get it's oxigen burnt.

Diesel efficiency is mandated by excess air coefficient. The more extra air you get into cylinders, the more efficient the engine is - hence a Diesel is fuel efficient when turbo/supercharged because you can get more excess air in. Gasoline engines are dictated by compression ratio. Different things.
BTW: are you people priming the fuel filter by the exit hole (easiest way to pour fuel as the inlet is a bent pipe)? Carefull there because you can get rubish in that will go straight to the pumps and injectors.
Better way: got to local Pug/Renault dealer/breaker and get a manual priming pump (black pear shaped thingy that's very usefull when you run out of fuel) and a length of adequate diameter hose. Fit one end of hose to inlet port of new filter and other end to exit of priming pump. Fit car hose to inlet side of pump and pump till fuel comes out of exit hole of filter. Remove non MB parts and fit everything else as was with new sealing bits of your choice.
Beats having to have fuel available and making a bigger mess with pouring potentially dirty fuel into a little hole, etc.
Did mine like this and engine started as usual with no fuss at all.

 

[c240yaz]

Hi everyone first day on here ! Got a 2000 e320 cdi and enjoy doing my own servicing ( honest the wallet busting merc prices have nothing to do with it) .Fitting new fuel filter so does anyone know the procedure for removing and re-fitting the circular fuel line clips , ie are there special pliers required ?

TheKat, Back to original post.

Did you get the clips off OK and fit the new ones, with the filter ?

 

[Dieselman]

Ok, I said I would update on the filling the diesel filter with engine oil, so here it is.

So did it blow or did it go.?

Having asked about what exactly was used in the commercial lorry and heavy plant garage I have been informed it was hydraulic oil, and have also been told of using standard vegetable oil.

I had some old 15w40 knocking around so used that and would agree this is probably a bit thick but have only used 5W40 previously.

Anyway back to the filter change.
Removed old filter to find the centre seal was damaged. This wasn't in itself causing a problem but the new filter is of different construction having a steel support ring instead of plastic.

Changed the filter and filled the new one with engine oil to prime it and turned the key.
Due to the fuel running back down towards the tank when the old filter was disconnected the car started then stopped as the air was drawn in.
Kept turning the key for a few turns until the engine fired up.


There was no smoke on startup as the oil ignites well. This pic shows the exhaust with engine running about 30 seconds after start-up. The spots on the floor are condensation.

There was less smoke on start-up than when running on Bio-diesel.

Because I was interested I decided to take the filter apart to see the state of the filter paper and whether oil would pass through Ok.
The filter was black, not sure of the colour of the new paper as you can't see it inside the cannister normally, although I'm sure this is due to the cleansing effect the bio-diesel has on the fuel system. There were no particles or dirt on the filter paper.

I filled the cartridge with oil and watched it drain. Initially the oil flowed readily through the paper then as the level dropped it ran slower.

You can see the oil dripping in this pic. the shiney parts are oil passing throught he filter paper.

A standard oil filter is about 25 microns due to being a full flow, volume filter so has to create no restriction. A diesel filter is about 8-10 microns to clean further and because the flow rate is less. A bypass filter can be down to 1 micron.
Engine oil will pass through a bypass filter so will definitely pass through a diesel filter, especially as the lift pump generates 25psi to push it through.

Thought you might like to know the outcome.