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  1. pmbrunelle

    Dynomometer

    I once tried to do tests on a Mustang dyno, with the vehicle speed near zero (less than walking speed), and the combustion engine operating near full torque, holding the clutch at its friction point. That did not go well; I tripped the overload protection of the dyno and the rollers went free.
  2. pmbrunelle

    Right ISO fit for a bearing in a aluminium housing

    I have used tolerance rings a few times; the waves are not necessarily equal all around, and there is a necessarily a gap between both ends of the metal strip, so these factors will result in some eccentricity, which may affect your shaft centre distance. Also, the tolerance ring is springy, so...
  3. pmbrunelle

    Low-throttle driveline oscillations

    I unplugged the oxygen sensors, and then a bunch of oscillations smoothed out; the driving became better. It looked like this was a big factor. Then, I reconnected the oxygen sensors, power-cycled the ECU, and the system remained non-oscillatory :rolleyes: Intermittent borderline problems...
  4. pmbrunelle

    Low-throttle driveline oscillations

    Well now it's two engines (on two different platforms), but the engines are similar. They are 1L, 2 cylinders, 4-stroke, idle around 1500 RPM, rev limit around 8000. With the OEM calibration, cruise was in the 4000+ RPM range, but some users could perceive this as buzzy/unpleasant. I am trying...
  5. pmbrunelle

    Low-throttle driveline oscillations

    After a few weeks on another project, I was able to return to this topic! Varying the CVT ratio didn't have much effect on the shuffle. Yes, it seems to be related to this! The engine calibration has an Eco/Sport mode selection. Changing between those two calibrations (presumably with some...
  6. pmbrunelle

    Low-throttle driveline oscillations

    In a semi-related topic, an overly sensitive throttle and strong engine can cause driver-induced oscillations, where acceleration causes the driver's foot to lift off the pedal, then the wheel torque is reduced, the driver's foot falls backs on the pedal, and so on. This can be worse on bumpy...
  7. pmbrunelle

    Low-throttle driveline oscillations

    What are you getting at with the powertrain configuration? The number of gear reductions, shafts, joints, and opportunities for backlash? Whether the torque that acts on the engine mounts is equal to engine torque, or if it is also multiplied by the transmission and/or final drive? I don't...
  8. pmbrunelle

    Low-throttle driveline oscillations

    Good guess! It's happening at about 2.5 Hz. I don't have direct access to the tonewheel sensors, only through their respective modules and the CAN bus, but since the oscillation is a fairly slow phenomenon, the speed information available through the CAN bus might be fast enough. Suppression...
  9. pmbrunelle

    Low-throttle driveline oscillations

    I think this is called "shuffle". The nearly brand-new vehicle did not oscillate with its factory transmission. When we fitted a prototype transmission (also a CVT) to it, the oscillations appeared. Nothing else changed; same engine/diff mounts, same tires, same half-shafts, etc. I have full...
  10. pmbrunelle

    Low-throttle driveline oscillations

    Sometimes, when driving slowly with near-zero torque (torque converter locked up), there can be an unpleasant bucking sensation in the car as the engine inertia oscillates with the driveline lash and compliance. I do not think that consumers would accept this behaviour anymore. How are these...
  11. pmbrunelle

    Pressure angle for helical gears, with tangential, axial and radial forces.

    I'm pretty sure I know which application you're talking about [wink] The driven spur gear has a simpler shape, so it is perhaps easier to think about things from the perspective of the spur gear. On the face of the spur gear, there is a contact point (you must find this point). At the contact...
  12. pmbrunelle

    Clutch material

    Is this meant for regular slippage, or only intermittent duty as a "fuse"? For intermittent duty, you may consider a tolerance ring. The tolerance ring uses grease on the friction surface, so you don't have to worry about grease contamination.
  13. pmbrunelle

    Pushing clutch help

    I would look into making the pedal longer if possible, to increase the travel of the pedal. Or, arrange the pedal such that it swings through a greater angle. It is possible that it's the peak force which is tiring, not the work. Performing the same work, but over a greater distance may be...
  14. pmbrunelle

    Off Center Boring of Automotive Wheels

    I work for an automotive (mostly) tier 1 supplier, so I am aware of the need for poka-yokes and the trouble that complicated designs/procedures can bring to production. I was a child in the 90s, so I don't know much about that era, besides what I've been able to pick up doing...
  15. pmbrunelle

    Off Center Boring of Automotive Wheels

    Were wheels produced with a single (nominal) dimension of runout (perhaps optimized for a certain statistical variation of tire uniformity), or were there different part numbers, with each part number having a slightly different runout dimension?
  16. pmbrunelle

    Off Center Boring of Automotive Wheels

    Are the conical/tapered lug holes also machined off-centre in this idea? If the bore moves, but the lug holes do not, then that offset would created unwanted stresses in the lug studs. Were the lug nut seats flat in this idea? **************************************** If a wheel's off-centre...
  17. pmbrunelle

    Hardness - Print Callout

    So, if I understand correctly, the forging vendor is not responsible to meet the 50-60 HRC core hardness requirement which exists only on the finished part print.
  18. pmbrunelle

    Hardness - Print Callout

    What do you order from the vendor? A finished part (with associated core hardness spec), or a forging (with ill-defined hardness)?
  19. pmbrunelle

    Hardness - Print Callout

    I agree with the interpretation of your vendor of checking surface hardness. It sounds like your print didn't adequately describe the part you need, so you received something slightly different than your expectations.
  20. pmbrunelle

    Screw Torque Specification/Calc

    You probably need to guess at the load path as MintJulep suggested. Then, make a free-body diagram of the clamp piece, and work out how much screw force you need to keep things in place. ******************************************************************************** I often use this screw...

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