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Recent content by charliebPE

  1. charliebPE

    direct injection diesels

    kimbo1 Have you tried dieselnet.net? Also, perhaps you have a specific question? Charlie
  2. charliebPE

    SPICE models for valves (vacuum tubes)

    Brian, A month ago, I was in the engineering library at my local university, Iowa State in Ames, and casually perused the TK7800 section. There was a 1960s book there that included early analytical models of transistors as well as late analytical models of vacuum tubes. I did not write down...
  3. charliebPE

    A Circuuit to Drive Ultrasonic Transducers

    Nbucska, Ahh, but I'm cheap! The ultrasonic magnetostrictive transducer itself is my filter. Any harmonics that survive eddy current attenuation will then be severely attenuated because the transducer is driving a waveguide with a non-linear shape, which the math tells me will only resonate...
  4. charliebPE

    A Circuuit to Drive Ultrasonic Transducers

    Hello Peternz and Mmartens, Having worked with magnetostrictive transducers and having been frustrated with trying to find reasonable power supplies available off the shelf, I'm designing my own. These comments will apply equally well to a piezo device. I've chosen an LM555 timer running in...
  5. charliebPE

    DI Engines

    Wow! I go away for a couple days and come back to find a lot of interest in my question. Thanks, especially to Tom, for providing the technical explanations as to why GDI doesn't seem to work. As I read it, the fundamental physical problem is that liquid fuel droplets are too large and...
  6. charliebPE

    DI Engines

    Thanks for your info Tom. I checked out Orbital's extensive website, but could not read all of it. Looks like they have some interesting technology and I hope it gets over here. But it surprises me that 3 companies; Bosch, Mitsubishi, and Siemens; all make the same mistake and fail miserably...
  7. charliebPE

    DI Engines

    It surprises me that diesel engines inject fuel directly into the combustion chamber but this seems to have never been the case with production gasoline engines. What is the reason for that? I saw on Bosch's website a claim of 15 to 20% gasoline fuel economy improvement for this one technique...
  8. charliebPE

    Propane enrichment for diesels

    "The onboard computer has no way of knowing how much power the engine is producing, as long as the diesel profile is not altered, and the RPM is still within governing limits." Just thought I'd let you know that at last there is a viable concept to cheaply and easily measure shaft...
  9. charliebPE

    Help for system vibration coupling problem

    I'll add that I have yet to find a transducer that did not introduce harmonics due to inherent non-linearities. Neither piezoelectric ceramics nor magnetostrictive materials, both of which will operate in your frequency regime, are free of this problem. Be that as it may, a dynamic system with...
  10. charliebPE

    Non-Contact Torque Sensor

    Hello, Does anybody out there know of a good non-contact torque sensor? Thanks. charliebPE
  11. charliebPE

    Knowledge of Helmholtz Resonators

    Hello gtp, A helmholtz resonator is simply a fluidic spring/mass system, where a column of fluid in a neck is made to interact with a closed cavity. The compliance of the cavity volume interacts with the inertance of the slug of fluid in the neck. The calculation details involve the bulk...
  12. charliebPE

    Ultrasonic whistle design needed

    Hey jkftl, What do you need a whistle for when atomizing? Perhaps what you really are looking for is a way to atomize a liquid using ultrasonics? If so, there are ways to make this happen using an ultrasonic transducer. Check out www.uia.org or I have several other applicable links listed on...
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