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Written by Eric Schacht
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Saturday, 10 May 2008 |
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There are always going to be some bumps and obstacles along any road, but what counts is how you handle them. I am proud to say that our team is second to none when it comes to problem solving. When the chips are down and the stakes are high everyone on the team pitches in and things start to happen. Over the last week the Exhaust has completed every stage of testing to verify its functionality and tune it for maximum efficiency. This testing included properly atomising or vaporizing diesel fuel with a high voltage electric heater. Then after finishing this it was necessary to produce a reliable flame with the proper fuel air mixture. Completing this also involved a reliable ignition source. Before that it had to be determined how to schedule a regeneration cycle based on NOx reduction efficiency. That was determined using carbon monoxide injection, which is now replaced with a diesel powered regeneration unit. Then if all these things don't sound like enough fun you have to now determine the proper regeneration timing and cycling to produce a safe and reliable reduction in NOx emissions. All this testing has been completed and the system has produced as high as 95% efficiencies, which when averaged with regeneration efficiencies can produce an overall efficiency of 85%. This all comes with only a 1% penalty in fuel economy! So what would have been the bumps along the way?? Well where do I start? First the fuel pump broke because the fuel chamber was too tight. Then the glow plug wouldn't get hot enough to ignite the flame. Next the flame was back firing and not mixing correctly due to strange flow and required a nozzle. Following this the valves began leaking and the system had to be pulled down and repaired. Last 2 cartridge heaters fried, one mosfet, and an RTD. So does the system sound faulty??? Well IT WAS!! The GOOD NEWS now is it is NOT ANYMORE! With each problem came a better and brighter solution. The fuel pump was replaced with a small valve and run off the engine fuel pump making a much more compact and reliable solution. Then the glow plug was replaced with a super high energy igniter. Next the valves were resealed with no other solution then a simple well placed weld to hold the seals in place. So what about the heaters the mosfet and the RTD?? Well simple the RTD was damaged on install and failed. The new one is not damaged and therefore will not fail. What is the result of all this mechanical jargon?? One of the most elaborate displays of automotive engineering at OSU today. From a Ph.D project in the lab to a working system on a vehicle this has been an extraordinary accomplishment for the OSU ChallengeX team!! So everyone cross your fingers and hope that everything goes smooth as silk and the system works like a charm!
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