LPG, Bio Diesel, Hydrogen, Fuel Cell Questions and Answers last answered over 2 years ago.
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I used a modified Eckes system for a while- and only had two no starts during winter. The modifications added a Vauxhall diesel electric heating element which I never properly tested to see how effective it was, I will get back to it one day and test it though.
I have a problem recently that I use a Fuel Filter almost every month, which is a pain. I run on Bio diesel made from veg oil (SVO), what makes the filter stop working (I presume it is the filter) I get loads of little bubble in the fuel going to the pump, at idle the engine copes, but when you try to drive it cuts out. Happened this morning on the way to work I've bypassed the filter for now, but I will need to buy another tonight.
I looked at the Eckes system picts you kindly provided.Maybe its a filter problem due to heat and using biofuel.There is a seller on ebay that has some manufactured heated diesel filters .Can any one advice from where to obtain upgraded fuel injectors for biofuel?.
I am not heating the diesel. I have a twin tank system so I start on cold unheated diesel with a small filter between the tank and the IP. the return goes to the small diesel tank. A jerry can in the void behind the battery.
When warm I then switch my 6 port pollak valve to the main tank which holds neat unmodified filtered used cooking oil from the local pub. no molestation with methanol or hydroxide, just used oil. The oil goes through the Eckes and into the IP. the Pollak valve is used to switch the return so this now goes back into the filter and into the IP again - a looped return, whereby the eckes repeatedly heats the same fuel rather than getting new cold oil from the tank.
I have not tested the temps I am achieving with this setup yet. I may find that I am not getting the fuel hot enough and need to fit a plate heat exchanger as well as the eckes. If I do, I will tee the return after the filter to radically decrease the flow going through the filter since this puts less strain on the pump.
One other thing regarding using just an eckes and no other heating. When I first switch to veg I have a hot eckes and below the oil cooler of the eckes is a cold filter full of very thick oil. The pump does not like sucking full rate fuel flow out of a cold filter so I am stressing it at this point until the filter canister is hot - this is probably a better reason for me to be also fitting a plate heat exchanger, so that as mentioned above, loop after the filter and only filter at the rate the fuel is being burned.
I'll do some temp tests soon and report back, but I will likely be adding a heat exchanger to my system soon regardless of temp for the cold filter of oil on switchover and stressing of pump reason.
Louey, the air sounds like a result of the filter clogging, this cuases a vacuum in the line between the pump and the filter since the pump is sucking and little or nowt is coming through. The vacuum finds the weakest point in the fuel line (either the filter seal, the hose tail fitting, banjo bolt seal or whatever) and draws in air. If you get this you know that there is a blocked filter AND you have a rather loose seal somewhere.
The filter clogging sounds like it could either be dodgy fuel (lumps in it - not filtered correctly) , or dodgy fuel (nasty solvents in the fuel that are stripping the insides of your fuel lines) what does the filter element look like when you need to do a change?
just_vegin wrote:The fuel coolers are on the PD engines after the pump... the pressures in the fuel system are seriously high and as a result the fuel gets extremely hot and it needs cooling before being returned to the tank.
And common rail. It could never exceed coolant temp so why do VW and others bother with these coolers if not for optimum performance/economy. Actually the PD return fuel has been under very little pressure compared to a convential pump.
Well, I think I have some pie of the humble variety to eat...
The fuel coolers are in the fuel return lines of the PDs - no question.
but it is not just for safety reasons...
Here is a quote from page 1.17 Haynes manual on diesel engines. Regarding pump injectors (PD)...
"Because of the extremely high fuel injection pressures, the fuel in the return line becomes very hot, and a fuel cooling system is used to cool the escess fuel before it is returned to the tank. Despite the obvious effect on safety, if the fuel were not cooled, the fuel temperature in the tank would rise" hence temp of fuel being delivered would rise and hot fuel reduces fuel delivery from injectors, blah blah, ecu compensation for hot fuel blah, blah..."cool fuel gives improved combustion and hence improved engine efficiency"
I am totally wrong then that the engine will run as efficiently on hot diesel as cold. I have read from a good source that there is very little thermal expansion of the fuel so maybe it is to do with the surface tension or viscosity....or is it purely the thermal expansion? I wonder what the difference in efficiency is? I can get 55 to 60mpgs in my wife's 1.9TDi passat when running on hot vegoil I wonder if I would get the same were it hot diesel!!
whatever it is, I don't personally heat diesel, just vegoil...although the well proven smartveg system would show that there are no long term ill effects of running on heated diesel
oh yes, and the coolant system used is divorced from the engine coolant system so it does not get so hot. correct again Andy!
just_vegin wrote:
The filter clogging sounds like it could either be dodgy fuel (lumps in it - not filtered correctly) , or dodgy fuel (nasty solvents in the fuel that are stripping the insides of your fuel lines) what does the filter element look like when you need to do a change?
I shall have a word with my supplier then - I know he wasn't pleased with the delivery he got on Tuesday, it was dropped of by his supplier and it was 80 degree C!!!!
I'm not keen on having to change my filter almost every month
he should tell you if there has been a problem with it.
It may also be years of guff cleaned off the inside of your tank. This seems to be something that is mentioned a lot with biodiesel - I've never experinced it having only used straight oil which is not so caustic.
just_vegin wrote:
I am totally wrong then that the engine will run as efficiently on hot diesel as cold. I have read from a good source that there is very little thermal expansion of the fuel so maybe it is to do with the surface tension or viscosity....or is it purely the thermal expansion? I wonder what the difference in efficiency is? I can get 55 to 60mpgs in my wife's 1.9TDi passat when running on hot vegoil I wonder if I would get the same were it hot diesel!!
If you could get injectors big enough and a pump able to pump cold oil properly it would work great.
The heat problem from PD's is not from heat from being put under pressure but from the fact it circulates inside the cylinder head so acts as engine coolant.
Theres a company in Lancs called diesel bob www.dieselbob.co.uk who do the upgrades for injectors and pumps for bio fuel .I got a price for the injectors . just-vegen "on your set up you said" The oil goes through the Eckes and into the IP. the Pollak valve is used to switch the return so this now goes back into the filter and into the IP again - a looped return, whereby the eckes repeatedly heats the same fuel rather than getting new cold oil from the tank . The return line to the tank on a standard filter has a valve stated as from a peter russek manual control valve below 15c to filter open above 31c flow to filter closed.Your pollak valve as you discribed is switching the return.Question i am asking you but others might help answer.Would there be a fuel pressure build up in your filter as it does not return to the tank.
I've bypassed the filter for now, but I will need to buy another tonight.
