General Volvos and chip fat

[mickythemechy]

Engineer is wrong to say its legal,unless you declare it to HM revenue you cant use veg oil from tesco or anywhere else in a motor vehicle on the public roads as you havent paid tax.Google veg oil in cars there are a ruck of sites on this issue.Mick

[DLM48]

Originally Posted by mickythemechy

Engineer is wrong to say its legal,unless you declare it to HM revenue you cant use veg oil from tesco or anywhere else in a motor vehicle on the public roads as you havent paid tax.Google veg oil in cars there are a ruck of sites on this issue.Mick

OH MY here we go again

Historically in the U.K, H.M. Revenue and Customs (HMRC) levied a fuel duty of 28.35 pence per litre for all vegetable oils that meet the fiscal definition of what's confusingly termed ‘biodiesel’. This represented a discount of 20 pence on the normal duty level for conventional diesel.

However, it has cost HMRC more to police and process payments from private users/producers than the revenue generated. From 1 July 2007, users/producers of 2,500 litres or less per annum will no longer be required to submit a monthly return (although existing producers will be required to keep basic records for an additional 6 years). This means the use of compliant vegetable oils will be DUTY FREE for the private motorist.

The HMRC’s web site - http://www.hmrc.gov.uk/briefs/excise-duty/brief4307.htm

[DLM48]

have fun

http://www.dieselveg.com/vegmodel.xls

regards

[tfb]

Originally Posted by DLM48

In the first diagram use the thermal switch to drive a two pole relay and you can use one pole for the existing thermal switched circuit and the other to switch the + 12V power after the filter heater relay or the return to the filter heater. The LEDs will still have a return so should work OK that way the purge switch wont power the filter heater IF the thermal switch is active. What is the box to the left of the thermal switch and the switch in the line above it the heater relay? if so it is open when it should be closed as the thermal switch is closed? OR you could move the purge switch line to between the two relays and isolate the heater relay with a diode so the purge switch wont activate it and only the thermal switch can.

Yep, the box is a relay for the filter heater, it's 180W so draws 15A and will need to fed over a relay. Also might have drawn the contact as normaly open instead of normaly closed....too much beer to think straight at the moment!. Will have a better look when sober and thanks for the suggestions

Also forgot to add that the +12V is from a swithced supply (i'll use the feed to the IP fuel valve ), but the feed for the heater will be direct fromt he battery.

TFB

[RoyMacDonald]

Originally Posted by David Humphrey

I have a 740TD and have read this thread with interest and would be grateful for any advice on how much vegetable oil I can mix with diesel during the winter months in the uk without running into problems with a totally unmodified vehicle.I should add that my journeys are quite short.
David

What people seem to think is that if you can start up on SOV and diesel and run OK that everything is fine, without considering what happens when you stop and switch the engine off. Two tank systems are used for a reason. When you switch the engine off the fuel you are using will be left all over the the injectors, valves, pistons, etc. The SOV will cool and get baked onto everything.....the dreaded knacker laquer. In a robust engine like the Merc 190D or the Volvo 740 TD you will get away with it for several years but it will kill the engine eventually which is why I think it's worth doing the job properly and not wrecking fine engines.

Roy

[tfb]

Electrical drawing Rev2. Updated with DLM48's comments.

1) Auto/Purge switch moved to between the Changeover and Filter heater relays
2) Diode added to prevent a back feed picking up the Filter Heater relay when the purge switch is operated
3) More labeling added
4) Now shows which parts of the cct. are fed from the permament live and which are fed from a switched live
5) www.rswww.com down so I can't spec the relays

Note cct is show in it's de-energized state, that's why the contact for the filter heater is shown as open

Regards
TFB

[DLM48]

Originally Posted by RoyMacDonald

What people seem to think is that if you can start up on SOV and diesel and run OK that everything is fine, without considering what happens when you stop and switch the engine off. Two tank systems are used for a reason. When you switch the engine off the fuel you are using will be left all over the the injectors, valves, pistons, etc. The SOV will cool and get baked onto everything.....the dreaded knacker laquer. In a robust engine like the Merc 190D or the Volvo 740 TD you will get away with it for several years but it will kill the engine eventually which is why I think it's worth doing the job properly and not wrecking fine engines.

Roy

Without getting into a war - there is theory and practice - plenty of theoreticians support your view - but practice does not seem to follow theory here. There are many many examples of single tank cars running without all these theoretical problems which have done hundreds of thousands of miles without dying a premature death due to running on SVO or even WVO. In fact there are two bench mark cars/engines the Merc one with the inline Bosch IP and the VW Golf/Rabbit/Jetta engine which is the baby version of the engine in the Volvo. Identical in every way apart from being a 4 cyl engine and not a 6 cyl one. Obviously the people who supply two tank systems are somewhat supportive of the view that you hold. BUT for sure i have found that theory is flawed here running my Punto with the rotary pump that wont work with cold SVO has been a painless and interesting experiment. It seems strange to me that with all this theory about and all the experts predicting doom and gloom we have yet to see any stripped down engines showing these engine killing symptoms/effects. SVO is actually a 'better' lubricant than PD and significantly 'better' than BD in many many areas not least being greener and less 'harmful' to the pipes pumps and seals in your 'typical' diesel vehicle. Running on a single tank VO system is for sure less complex - both the Merc and the Volvo IP's can 'handle' the thicker VO without any problems - though i 'think' i heard of one D24T camshaft breaking' not really sure if this was a VO issue. The only problem you will have is winter cold starting - probably easily and cheaply solved by using longer hotter glow plugs with perhaps a longer heat cycle (if you are technical) and a electrically heated fuel filter insert easily obtained from a scrap yard many diesel cars have them including the Fiat Punto apart from this 'cold start issue' i dont see any others - for sure not that knacker lacquer nonsense. Sadly we all dont have the time and the energy and the finances to do a proper investigation of what works best here so it is all a matter of opinion and sorting out the wheat from the chaff or in this case the oil from the rape seed is not that easy.

Just my view(s) of course

[tfb]

Well, I had a few minutes over the last couple of days to tinker with Volvo . I was curious to find out the operating specs of the Elsbett electric fuel heater, the new glow plug control and the fuel temperature.

The Elsbett supplied control relay keeps the glow plugs running for 180 seconds after the engine starts as long as the coolant temperature is under 70 degrees C. If the coolant temperature reaches 70 degrees C within that 3 minutes, then the glow plugs are turned off. If the ignition is turned on but the engine not cranked then the glow plugs turn off after 14 seconds. The electric fuel filter heater is also controlled by the glow plug control circuit.

I have had my doubts as to the effectiveness any form of electric fuel heater, I can't see how you can dump enough energy into the fuel to make much of a difference. As the Elsbett heater is only running for the same length of time as the glow plugs, this really doesn't allow much time for heating at all.

I got hold of a little inline fuel filter and melted a hole in the side and glued a temperature probe into it (see attached pic). I then put the filter between the heated filter and the injection pump. With the car parked on the drive and the engine idling I recorded the temperature every 10 seconds. I did 3 test runs. 2 were for 4 minutes and one only lasted 2 minutes as I was interrupted with “ Daaaaaddd, George has stuck my Polly Pocket up his nose!”.

The three runs were:
1.Coolant heat exchanger in circuit and electric filter heater on
2.Coolant heat exchanger in circuit and electric filter heater off
3.Coolant heat exchanger out of circuit and electric filter on

I did each run in the morning after the car had been standing overnight to ensure that the engine and fuel were at ambient temperature.

Interpreting then results:
The initial fuel temperature varies for each run, as this was what the ambient temperature was at the time, the important part of the results is the shape of the curve which is the rate of increase.

As can be seen from the resulting graph (see attached file) There is no increase in fuel temperature for about 60 seconds, then the tests with the coolant heater exchanger in circuit show the temperature starting to rise. The electric heated fuel filter takes over 90 seconds before any rise in temperature is seen. I suspect the slight fall in temperature during the first 50 seconds of each run is due to my handling of the temperature probe warming it up slightly and it being cooled by the fuel. The variation is only 0.5 degree but as it occurred on every run it can't be written off without an explanation.

Despite the low rate of increase seen from the electric fuel heater, I will leave it in circuit in case at some point I start to use waste vegetable oil and it should help prevent the filter from clogging up with wax before the coolant has hit 70 degrees and I switch over to veg.

I did one more test run of taking the car for a quick spin around the Fens (about 10miles) and found that the fuel temperature stabilized at about 62 degrees C and it took about 2.5miles for the coolant temperature to reach 70 degrees C and the Elsbett supplied temperature switch to operate.

Next planned experiments are to measure the viscosity of diesel, diesel/SVO mix and pure SVO at various temperatures.

Regards
TFB

[RoyMacDonald]

Originally Posted by tfb

I have had my doubts as to the effectiveness any form of electric fuel heater, I can't see how you can dump enough energy into the fuel to make much of a difference. As the Elsbett heater is only running for the same length of time as the glow plugs, this really doesn't allow much time for heating at all.



Next planned experiments are to measure the viscosity of diesel, diesel/SVO mix and pure SVO at various temperatures.

Regards
TFB

There are already comprehensive tests on line of the viscosity of diesel and SOV at different temperatures. No mix temps though. I can't remember where I saw them though, but you might like to brouse for them. I'll post if I come across them again. The tests might have been related to the fuel injector induction heater I posted about previously.

Thanks for the useful info. I can see why Smartveg have chosen not to bother with fuel heaters now.

Roy

[RoyMacDonald]

This isn't the article but it does have some information and gives information on Elsbett's tests & reasoning. Also of note is the use of Plantmot engine oil and the absense of lacquer.

http://www.ilot.edu.pl/2005%201_2%20...bialkowski.pdf

Roy