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Semelhante a BIO3.0 Biodiesel Performance and Vehicle Maintenance
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BIO3.0 Biodiesel Performance and Vehicle Maintenance
- 1. Biodiesel Technical Training Course BIO 3.0: Biodiesel Vehicle Maintenance and Performance Presented by the National Biodiesel Board
- 22. Biodiesel Performance: Some Examples of Lab Durability Studies
- 27. Overhead Components Top of cylinder head No sludge deposits Bottom of cylinder head Deposits comparable to #2D Intake Valves Exhaust Valves Results are typical for this type of test with #2D diesel fuel
- 28. Power Transfer Components During teardown, the crankshaft was found to be in very good condition, and results were comparable to #2D diesel fuel test. Component Comments Cranckshaft Gear Meets rebuild spec Cam Gear Meets rebuild spec Cam Bushing Meets rebuild spec Fuel Pump Gear Meets rebuild spec Cranckshaft Meets rebuild spec Lower & Upper Bearings Normal wear Connecting Rod Meets rebuild spec Connecting Rod Bushing Meets rebuild spec
- 29. Power Cylinder Components Crosshatch visible in all six cylinders. Results comparable to #2D diesel fuel test. Ring Grooves Anti-Thrust Side Cylinder 1 Top Piston Piston Bowl Front Cylinder 1 Minor staining Component Comments Piston Normal light wear and deposits. Cylinder Liners Normal light wear. Top rings Normal uniform face wear. Top and bottom side look typical. Middle rings Normal face wear. Top and bottom sides OK, and light carboning. Oil rings Looked good. Very little wear.
- 30. Cooling and Lube Components There were no failures found on the cooling and lube components. The wear and deposits found on the parts were normal and consistent with findings found on parts that ran with #2 diesel fuel in similar tests. Bottom (Oil) Piston Rings Cylinder 1 Top Cylinder 6 Bottom Component Comments Oil pump No issues Oil cooler head No issues Oil cooler cover No issues Oil pressure regulator/bypass No issues Piston cooling nozzles No problems due to B20. Oil Pan Normal Oil suction tube Gasket showed good imprint of seal Turbo coolant/oil lines Normal
- 31. Air Handling Components Carbon deposit layer was generated on the passage and inside parts of the EGR valve , but thickness was very thin and condition was dry which is normal for this durability test. Component Comments Exhaust Manifold No issues. EGR Cooler No cracks, light coating of soot on inlet and outlet tubes. No soot in inlet diffuser. Findings good overall. EGR Valve Looked good. Normal soot accumulation. EGR gaskets, hoses, tubes, shield, mounting plate, crossover No issues found due to running with B20.
- 32. Aftertreatment Components Component Comments Diesel Oxidation Catalyst (DOC) Looked good. No face plugging. Blockages found appeared like debris and substrate material. Debris was analyzed under Electron Dispersive Spectroscopy (EDS), and all debris found is expected in a typical DOC after 1000 hr of operation, whether fueled with ULSD or biodiesel. Diesel Particulate Filter (DPF) Inlet face showed signs of ash build up, but similar to diesel fuel for this type of test. Outlet looked good with no signs of soot. No failure found. Inlet and outlet section Looked good. Gaskets Looked good.
- 33. Fuel System Pictures Stage 1 Plunger Needle No marks on needle surface or the edge. Plunger Needle – Top View Some slight staining. Stage 2 Plunger Needle has some wear, but normal for this type of aggressive test. Plunger Orifice not clogged with oil sludge or deposits
- 34. Fuel System Components Rail and fuel lines Rail – No abnormal wear. End Fitting – No unusual wear. HP Fuel Lines – No visible structural deterioration or cracks observed. Mechanical Dump Valve (MDV) No unusual wear, deterioration or sludge buildup observed on plungers, plunger seats or orifice. 1) Stage One Plunger – No wear visible on the needle surface or the edge. Some slight staining seen on plunger base. 2) Stage Two Plunger – Some wear, but normal. Plunger orifice not clogged with oil sludge or deposits. Injectors Injector performance test and photos indicate that the injectors were consistent with injectors that ran with #2D diesel fuel. Soft Lines No visible damage to any section of the internal wall of the used fuel tubes indicating that the tubing liner material is resistant to the B20 temperatures and pressures during the engine performance test. Overall There were no signs of severe or aggressive corrosion pitting damage on any of the surfaces.
- 37. Fuel technology Combustion technology Aftertreatment technology Fuel system technology Better understanding of combustion Alternate Fuels (Biodiesel) Low sulfur De-NOx DOC PM trap Rate control High pressure Multi-injection EGR technology Others Control technology Technology Pathway
- 38. Sources for Filter Clogging: Petrodiesel and Biodiesel
- 46. Paraffin Wax
- 50. Un-reacted Off-spec Biodiesel: Saturated Mono-glyceride
Notas do Editor
- From the field experience, you can see that with fuel meeting the specifications, and a few simple precautions, users have a good experience with B20—maybe changing fuel filters initially, maybe a few more cold weather issues, but all of which can be handled by following the appropriate the guidelines. So we will review some of the lab experience related to biodiesel performance, and some examples of some pretty significant work that’s been done in cooperation with the engine companies, in terms of lab durability studies, both with engine durabilities and with engine oil impacts. The first of these will be with engine oil impacts.
- One of the reasons for that is some of the durability runs that had been done on B20 in existing engines. It’s fairly typical for an engine company to run durability runs with diesel fuel to make sure the engines they put out are going to perform well in the field over time. They do that with an accelerated program plan, and in this case, Cummins ran a 1000 hour durability on B20, with the objective to operate the engine for 1000 hours using B20 fuel and do a comprehensive analysis of the engine that had operated on the fuel with the same type of conditions that they would use for No. 2 diesel fuel. You see the test plan here, looking at 1000 hour test plan, 125 hours of initial break-in, measuring emissions, and then running the engine for another 875 hours for a total 1000 hours. Then they run the emissions again to see how the emissions of the engine might have changed throughout its useful life. Most of the time, the engine is run on an accelerated high load durability cycle to stress the engine out again, stressing the engine as much as possible to gain maximum potential negative effects, should there be any on the engine.
- The test engine used was a Cummins prototype 2007 ISL engine, six cylinder, 8.9 liter with 330 brake horsepower at 1150 ft lb of torque at 1300 rpm. It was outfitted with a diesel oxidation catalyst and a diesel particulate filter. That filter used the in-cylinder post injection for active regeneration. It had variable geometry turbocharging, exhaust gas recirculation with an inner cooler, and the Cummins proprietary fuel injection system. So it really had the latest bells and whistles on a prototype engine with both EGR and a diesel particulate filter. There were no NOx controls on this particular engine.
- The test cycle that was used had about 70% of the durability cycles at full load, so it accelerates through high load in a transient cycle, it varies the load and speed, and then it repeats those cycles anywhere from peak torque power to high idle to low idle to peak torque, and goes through that cycle over 1000 hours. The emissions testing that was done was according to the Federal Test Procedure. One cold start transient FTP test and then three hot starts, and then one set of Ramped Modal Cycle.
- The results for that engine are shown on this slide. Approximately 17,000 gallons of B20 was used during the test. The test went well and was successful. There were no biodiesel related failures during the test, no reported significant changes in performance of the engine. The engine performance was essentially the same when it was tested at 125 hours and at 1000 hours after the accumulated durability operation. The emissions results indicated that the hydrocarbon, CO and PM levels were not significantly different between the B20 and the ULSD in this particular test. We do see PM, CO and hydrocarbon levels on non particulate trapped engines, but with the particulate trap, the B20 didn’t provide that much more than the ULSD alone did. On the emissions also, the B20 was slightly higher in NOx, but is within the range that we expected to see for this particular test cycle and this particular engine. We may see lower NOx, in other applications or if a chassis dyno was used rather than an engine dynomometer. The fuel consumption was observed to be about 3% higher than the 2007 certified ULSD, which was within the expected range. That is about the expected range of the BTU content of the biodiesel.
- Here are some pictures of the components. We see the top cylinder heads had no sludge deposits. Deposits were comparable on the bottom of the cylinder head between diesel fuel and No. 2 diesel fuel. Both the intake and exhaust valves were typical for this type of test run on conventional No. 2 diesel.
- For the power transfer components, the crank shaft was in very good condition, with the results comparable to No. 2 diesel fuel, and at least in this particular case, no adverse impacts on any of the engine oil related areas. All of the components from the crank shaft gear to the cam bearing to the bushings, fuel pump gears, connecting rods, etc all looked normal and meet the traditional rebuild specs that we would expect for this engine operating that long.
- The power cylinder components—the crosshatch was still visible on all six cylinders, the ring grooves similar, the top of the pistons similar.
- Everything looked normal, and the same situation with the cooling and the lube components. No issues, no problems, just all around a clean bill of health.
- The same with the air handling components. There was a little bit of soot in some areas, but in the areas where there was soot, we would expect that with normal diesel fuel as well. So nothing out of the ordinary.
- The aftertreatment components—this was something that was of interest, because one of the questions was whether or not it would have an impact on aftertreatment, and in this particular test, the diesel oxidation catalyst looked good. There were some blockages found, but that’s normal for what we’d expect with diesel fuel. On the diesel particulate filter, and this was one of the runs with the diesel particulate filter after 1000 hours of operation, that looked good. And the gaskets looked good, as well as the inlet and outlet section.
- Here you see some pictures of injectors, plungers, etc. No issues to note there.
- The other fuels system components had no issues noted there either.
- In summary with this engine, it was a Cummins 2007 prototype with a particulate trap that was in-cylinder post injection for control with EGR and variable turbo charging, was operated successfully. No biodiesel related failures, engine performance with the same, emissions were the same. A thorough engine teardown analyzed pretty much all the parts that we could look at, and there were no failures related to B20, and the wear and deposits were consistent with what we’d see with diesel fuel. So a good bill of health, and really show that the ASTM specs and for biodiesel meeting those specs, even in this new prototype engine, is going to perform well for users in the fuel system.
- Most of you have seen this slide, which discloses the various technologies that are being applied to achieve Tier 2-4 emissions levels. I will only discuss the fuel system where the migration to common rail systems are a key leverage for achieving low emissions.
- This slide has both petrodiesel and biodiesel in its title because many of the issues associated with biodiesel filter clogging really aren’t biodiesel related at all. There are some that are related to biodiesel—or out of spec biodiesel—but its important for you as a diesel technician to know the difference so you can provide good advice back to your customers.
- Air enters all diesel systems and most of that time the air that comes in bring moisture with it. Air and moisture are the enemies of any fuel system—whether that system is petrodiesel or biodiesel. The presence of air will increase oxidation of the fuel over time. The best thing to do to minimize oxidation is to have good turn over of the fuel and not to store if for long periods of time. Most fueling systems do this as part of normal business, so it doesn’t end up being a problem. If there are systems where the fuel might stay around, fuel stabilizers are recommended as are desiccant dryers on the air vents which will minimize the potential for moisture contamination.
- Micro-organisms have been found in diesel fuel forever, and seem to be an increasing issue since the advent of ultra low sulfur diesel fuel. They grow at the water interface at the bottom of the tank, living in the water but feeding off of the fuel—whether that is petrodiesel or biodiesel or a biodiesel blend. If micro-organisms are present in a high enough quantity they can clog a fuel filter. They are relatively easily treated with a variety of conventional biocides which kill the organisms which can then be filtered out. Keeping the water out of tanks on a regular basis can go a long way toward reducing or eliminating micro-organisms. Filters with microbial growth appear black and slimy and typically have an odor different that is normal. There are a variety of microbial testing kits that users can buy to see if their fuel is starting to grow bugs. Its not desirable to regularly treat for bugs unless you actually have them, since you don’t want the bugs to develop a resistance to the biocide.
- The issue of water contamination is one that is poorly understood with biodiesel and biodiesel blends. This is primarily because of the issues with ethanol being water loving and people just automatically believe the same issues with ethanol exist with biodiesel. Pure biodiesel, B100, can hold slightly more water than diesel fuel—about 1200 ppm vs. 300 ppm) but even that is still a very, very small amount of water (0.12%) and is virtually the same as the amount of water gasoline holds (about 0.1%). In fact, biodiesel processors use the fact that water settles out of biodiesel, as many utilize a water wash step to helps to remove soaps and catalyst from B100. Data from NREL shows that B20 blends have similar water saturation characteristics as does petrodiesel alone. Both petrodiesel and B20 (or lower blends) hold somewhere between 100 and 300 ppm of water, with any more than that settling to the bottom of the tank. Keeping water out of tanks is always a good idea, and a good preventative maintenance program of checking tanks for water and if found removing that water is always a good idea for both petrodiesel and biodiesel.
- Reading of the bullets is sufficient here.
- Reading of the bullets is sufficient here.
- Here are some examples of sediment or Rust build up.
- Reading of the slides is sufficient here.
- Here are some examples of filters with paraffin wax.
- Reading the slides is sufficient here.
- Reading the slides is sufficient here.
- Reading the slides is sufficient.
- Here is an example of a filter that was clogged with out of spec biodiesel—saturated monoglycerides.
- You can use this handy checklist in the shop if you have filters coming in from the field and the user thinks it is a biodiesel problem. More than likely its not a biodiesel problem!
- Advise your customers of these simple steps which will help maintain high quality fuel and minimize filter clogging.
- To summarize, biodiesel and biodiesel blends are compatible with diesel particulate filters—and biodiesel provides some distinct advantages compared to petrodiesel alone (read bullets directly). There is one feature which is in the process of being investigated with some of the new particulate trap engine that technicians should be aware of. That feature is how the raw fuel is injected into the system to provide the fuel needed to burn the particles off the PM trap. There are two means to do this. The first way, which is used on most of the new PM trap equipped medium and heavy duty machinery in the US, is through a small fuel nozzle in the exhaust stream right before the particulate trap. Biodiesel blends—including pure biodiesel—work well with these systems. The second way is to use the injectors in the engine to vaporize raw fuel after combustion and during the exhaust stroke. This is called in-cylinder post combustion injection. Injection in this mode saves a fuel nozzle, but it creates more of an opportunity for fuel to hit the cylinder walls and get washed into the engine oil sump by the piston rings. This happens with petrodiesel alone, and the presence of biodiesel may make it a bit worse. Cummins did not identify this as an issue with B20 in the 1000 hour durability run on the prototype engine, and Ford doesn’t see this as an issues with their new engine, but some light duty car makers say blends over B5 are not recommended because of it. The jury is still out on this particular issue, but if it does happen you will see the level of oil on the dipstick actually go higher over time and if it goes too high that could cause the sump to fill up and cause problems or lower the lubricating properties of the oil. This phenomenon may require more frequent oil changes for B20 blends, or watching the oil level more closely with those models that use in-cylinder post injection but at present it only appears to be newest foreign light duty models that are affected.