Topic: SVO + WVO systems for diesel engines
By: Jim Burke, pres. of the Connecticut Biodiesel Co-Op.

'Credentials' - 3 1/2 years using biodiesel and wvo. 40k miles.
        1,000's of hours spent online researching and posting.
        This presentation is a summary of english language published reports,
                internet wisdom and personal experiences.

Why?  - commercial biodiesel is expensive, $3/gallon
      - homebrew biodiesel involves dangerous chemicals. Methanol, lye
      - fuel can be collected and filtered for 20 cents/gallon
        and 4 hours per month of labor for the average VW TDI driver.
      - 80-90% reduction in green house gas emissions.
      - vehicle emissions comparable to biodiesel.

Acronym's:
SVO - Straight Vegetable Oil, virgin unused oil. In Europe it conforms to Weihenstephan standard
WVO - Waste Vegetable Oil, used oil from a fryer usually.
FIP - Fuel Injection Pump

Biodiesel vs. WVO
You need to "convert the fuel or convert the engine".
Convert the vehicle once instead of converting the fuel monthly.
Less expensive than commercial biodiesel, less expensive and work than homebrew.
    
History - Early attempts to blend vo as a diesel replacement. Failure beyond 50% vo.
Is it safe?
    Estimate 8,000 conversions worldwide. Cars, motorcycles, trucks, generators
    even a train. Mack with 150,000 miles on WVO, TDI with 200,000 miles on SVO.
    No manufacturers advocate it. Elsbett does offer a warranty.

Have there been failures?
    Yes. Some engines are not suitable.
    Some fuel pumps have failed for unknown reasons.
    Piston coking may accumulate over a long time.
    Most results are field tests performed by individuals.
        Most failures are unreported and few failures are analyzed.

Viscosity vs. Temp Chart.
 - Heat > 32*F to prevent clouding at the fuel filter.
 - Heat to > 150*F to lower viscosity to 3x that of diesel.
 - asymptotically approaches the limit. The viscosity is little reduced from 150*F to 180*F.
   If further thinning is desired use 5% kerosene or gasoline.
   Significant emissions improvements noted by ACREVO report.
 
Overview of heating vo
  - By engine coolant. Through a heated tank and fuel lines. Hose-in-Hose
    Prefer stainless steel and aluminum to copper or brass. Greasel uses a copper
    coil wrapped around the fuel filter. Works better than you might expect. Gets
    the filter up to 150*F.
  - by electric elements.
     - Filter band heater used primarily to heat the filter above the cloud point so it
        can pass through the filter.
     - VegTherm installed just before the FIP. Heats to 150*F.

Dual Tank systems

Theory - Start on diesel or biodiesel, switch to vo,
     switch back 5 minutes before shutdown.

     Typical diagram
     Second tank heating - transmission cooler.
     Avoid copper tubing in fuel tanks, as corrosion and thermal cycling lead to
     cracks in the heat exchanger and coolant in the fuel.

Comparison
    VegTherm electric heater. Boosts temps to 150*F
    Vormax filter - good filter but takes up lots of space. Filter
        hot vo in the shop using an AC hetaed Vormax and pump.
    FIP acts as a heat sink, limiting the maximum temperature of the
        oil. As would the head and injectors limit to 200*F.


Single Tank systems
    - Better for around town driving. Dual tanks are required for commuting.
       [Northern europeans seem to do well and prefer single-tank designs.]
    - Must pre-heat the block to 70*F on 100% VO
    - Can start at lower temp.'s if thinned by kerosene etc...

Elsbett - injector conversion. Modify nozzle and raise the pressure.
      fuel filter heater till coolant temp reaches 150*F.
         electrics - slow glow plugs and filter heater, thermoswitch.


Thining when temps fall below freezing
   - What is the gel point? Temp at which it solidifies.
   - Necessary for single tank systems and biodiesel
   - Kerosene. 20% if >20*F and 30*F
            40% if >10*F and <20*F
   - always a good idea to use 5% kerosene or gasoline to reduce viscosity.

   Diesel may be used, but twice the percentage is needed to maintain
   the same gel point reduction as kerosene. Use your refrigerator and freezer to test
   samples in a jar.

   ACREVO study - The addition of 9% ethanol lowered the viscosity of vo significantly.
          9% ethanol/91% vo at 80*F equal to 100% vo at 150*F.
   But don't use ethanol, it may harm fuel seals and doesn't splash blend.
   Use 5% kerosene or gasoline.
   Roughly 1 quart / 5 gallons, a gallon / tankfull.
   This will provide a measure of insurance.
   Reducing the viscosity will provide better atomization.

Splash Blending
   Just pouring the fuels on top of one another. No stirring.
   It's best to mix blends of vo and kerosene or diesel in a 5 gallon jug.
   However, splash blending works if the fuel is filtered to 1 micron.
       
   
Suitable Vehicles
    Design of fuel pump and combustion chamber
    Pre-chamber / IDI Pre early 90's
    VW Rabbit, Mercedes, pre '94 Ford F-250
    DI engines with high swirl combustion chambers
    VW TDI, Cummings, Ford POwerstroke ?
    YES - BOSCH, Denso, Zexel, Stanadyne
    2004+ VW Pumpe-Dusse (?)60k miles
    
Unsuitable
    NO -  LUCAS /CAV fuel inj pumps ( British )
    Some GM, mid 70's 350 'diesel', Newer models with heat sensitive ECM near
    the fuel pump.
    Dodge Cummins 98.5 - 2000 with the VP44 BOSCH FIP.

Collecting
    Small restauarants, good quality, frequent changes
    Honey colored, not black.
    canola or soy are best. Avoid hydrogenated vo.
    Hydrogenated - Exposed to hydrogen gas under pressure.
    more waste but may resist oxidation.
    Original 4.5 gallon jugs, (wait for wvo to cool)
    or heavy plastic or metal cont. placed away from the rest.
    Keep closed to avoid rain.

    DON'T pull wvo from wvo collecters metal tank.
    The wvo belongs to the renderer.

    Collecting when temps fall below 30*F is difficult.
    Collect a reserve before cold weather. Otherwise use
    a shovel, an electrically heated Crisco' warmer or get the oil
    straight from the fryer.    

Collecting Equipment
    Don't buy the small 12VDC 10Amp electric pump for collecting wvo.
    It won't pull thick hydrogenated or cold wvo w/o blowing a fuse.
    Buy a bigger 12VDC model. Diaphram pumps are a good idea too.
    They pull the wvo in with a vacumn, so leaks don't lead to spills.


Filtering
    1. Settle for 2+ weeks
    2. Filter through washable nylon 100 micron mesh filter bag ( or panty hose )
         that is inside the final filter bag. Dump and wash the filter bag periodically.
    3. Filter through the 'final filter' 1 - 5 microns ( or old T-shirts ) Filter bag
    4. Heat a sample in a glass jar to 150 - 200*F. Let sit for 2 hours.
           Check for free water at the bottom, or layering.
 
    5. Acids - Mix 50% wvo and 50% water in a jar one minute.
         separate the water and check the water ph with litmus paper.
        Should be close to nuetral. If not you must remove free water
        and with it some of the acids. Or use the BioCar tester.
         If it tests outside the 2mg KOH limit, blend in fresh veg. oil, which is
         low in KOH.

The most sucessfull operation is achieved in Europe using SVO.
To replicate their sucess with WVO, you must ensure equal fuel qaulity.
Not practical to get it to conform to the Weihenstphen standard.
[Although you could get virgin soy oil at Costco's for $2.60/ gallon.]
The best way to do this is by removing entraped water.

     Entraped water removal. Heat to 90*F and maintain at 80-90*F for 8-9 hours.
       Allows water to settle out becoming free water. [ from Dana Linscott here]
       * excess water may promote etching by acids of the fip surfaces.
       * also 'micro pitting' by explosions/implosions of water micro droplets
             under pressure.
        
Fuel Quality Standards
      Weihenstephen
     real world - remove free water by settling  2wks+, pouring off the wvo
             and discarding the water. Filter to 1-5 microns.
             Heat to 90*F and let sit at > 80*F for 3 hours.
             pour or pump off the wvo leaving the free water at the bottom.

Emmisions
    Early tests in the 80's done on non-heated systems, not relevant.
    VO vs biodiesel vs diesel tests are very dependant on the vehice used.
    In general much less SO2 and soot. 80-90% less CO2 due to the plant cycle.
    Other emmisions vary. In general similar to biodiesel.
    Better than high sulphur diesel but worse than ultra low sulphur diesel.


Before conversion!
  - Clean your injectors. Take them to a local BOSCH service shop.
    Poor spray patterns are made worse by viscous fuel.
  - If it's an older vehicle. Replace fuel lines with new synthetic hose.
  - Drop the fuel tank and drain it. Check for a layer of wax lining the inside
    of the tank. Remove it with acetone. [Note: this is due to the use of parafin
    in diesel fuel. Fuel varies by region.]

Maintenance.
  - Check temperature of the fuel. Install gauge at the injector return line
    or use an infared thermometer.
  - Check crankase oil level. Looking for gelling or level rising!
    Unlikely problem in engines with <150,000 miles.
  - poor fuel economy as evidence of poor inj. spray as a result of coking.
 
Maintenance for the paranoid
 - Check cylinder compression before and at 10k intervals
 - Pull an injector. Look for coking.
 - Top speed test or timed run up a long steep hill.


Crises
 - If you forget to switch back and it won't start.
   - 3 gallons of very hot water poured directly on injectors and fuel pump.
     Avoid the electronics.
   - 1/4 second squirt of ether. Note: only in 'dire straits'
   - Tow vehicle to a heated garage. Keep above 35*F for 8 hours.
 

As an energy solution
 - Not enough vo to supply all our fuel needs.
 - Algae farms and smokestack fed algae.

For more help ask at the Infopop SVO forum.
or the forum of your kit manufacturer.

20 minute Q/A session


Web Links

Comprehensive SVO information Journey To Forever - SVO
My WVO conversion: Single tank Elsbett TDI
Infopop SVO Forum