rdcyclist
rdcyclist Reader
7/8/19 3:18 p.m.

I've got a new job, hence my lack of productivity relative to posting here not that anybody would notice since I'm not really prolific. The new job is with a laser and head-mounted display research company that mostly does gov't funded projects. There are many interesting things going on here but two of the completed projects have real motorsports application, IMHO. Of course my opinion is great and all that, but there are others out there with way more knowledge than I so I'm asking for that edification.

One is a laser-based torque measurement system requiring no direct modification to the shaft or supporting equipment to accurately (<2%) torque in just about any twisting force (torque) application. This was developed to measure torque in an F18 auxiliary power unit to increase the efficiency of the unit with real-time power measurement. This could be developed to measure torque on a single driveshaft for overall power or on individual shafts on an independent suspension vehicle. The output of the system could be read by any data-logging system. We believe this could be brought to market for less than a thousand dollars. Do we think this would be useful in a racing application? Is there already something like this? Would you buy this if you were running a big-ass race team?

The other is an inexpensive tachometer for turbochargers using a laser diode and receiver, sort of like the system under most computer mice. It would require a small hole to be tapped into the compressor side and will measure beyond 250000RPM. It has been tested to that speed and the system will cost about 300 bucks in production quantities. Same as above: Useful? Is there already something out there? Would you buy it?

Thanks, Mark

Robbie
Robbie UltimaDork
7/8/19 3:28 p.m.

Cool. I know of an 'on car' Dyno that you had to install between the driveshaft and diff or something. I think it was one of the big tuners, like aem maybe. I think it was $1500.

Never seen turbo rpm, but it would be useful I think in tuning!

Edit, yep. Aem: https://www.aemelectronics.com/files/pr/102811_Dyno-Shaft/Dyno-Shaft_PR.html

GameboyRMH
GameboyRMH MegaDork
7/8/19 3:35 p.m.

Turbo RPM sensors are already common in that price range, although they're mostly magnetic rather than optical since optical types aren't as reliable. Search for "turbo speed sensor."

morello159
morello159 Reader
7/8/19 3:42 p.m.

Yeah, turbo shaft speed sensors are pretty common. My turbo came pre-drilled for one and it's about $150 to add the sensor from BorgWarner. It's a hall effect sensor, similar to what your crankshaft or camshaft position sensor is.

How durable is your laser system, or sensitive to misalignment and debris? The underside of a car is a nasty place. Do you need to be able to see timing marks optically for it to work? 

rdcyclist
rdcyclist Reader
7/9/19 2:25 p.m.

The laser system for turbo speed should be very reliable. It just counts the vanes of the turbo as they pass by so all it needs is the threaded hole in the compressor. The sensor comes from a military application and is on the end of a 10-32 set screw. The Borg hall-effect sensor is not nearly as accurate but then it really doesn't need to be when measuring 150k rpm.

I'm hoping to put a pair of the turbo sensors on my S4 and see what's what. Film at eleven.

MadScientistMatt
MadScientistMatt PowerDork
7/9/19 3:13 p.m.
Robbie said:

Cool. I know of an 'on car' Dyno that you had to install between the driveshaft and diff or something. I think it was one of the big tuners, like aem maybe. I think it was $1500.

Never seen turbo rpm, but it would be useful I think in tuning!

Edit, yep. Aem: https://www.aemelectronics.com/files/pr/102811_Dyno-Shaft/Dyno-Shaft_PR.html

I believe those were taken off the market for reliability issues. I'm not sure if the problem was that it failed at measuring or failed at driveshafting, but the "no modification to the driveshaft" is a big advantage the Dynoshaft unit didn't have.

morello159
morello159 Reader
7/9/19 3:16 p.m.

Don't forget the cost of associated sensing hardware... 150k RPM is 2500Hz... and that's only if you're doing one for every rotation. Counting every fin would be an order of magnitude more. My ECU doesn't run that fast, much less sample that quickly. 

alfadriver
alfadriver MegaDork
7/10/19 6:32 a.m.
Robbie said:

Cool. I know of an 'on car' Dyno that you had to install between the driveshaft and diff or something. I think it was one of the big tuners, like aem maybe. I think it was $1500.

Never seen turbo rpm, but it would be useful I think in tuning!

Edit, yep. Aem: https://www.aemelectronics.com/files/pr/102811_Dyno-Shaft/Dyno-Shaft_PR.html

drive shafts with torque measurements on vehicles have been around as long as my career (27 years now), although if one came up with a non-contact way of measuring shaft torque, that would be totally awesome.  

And turbo speed sensing has been around for a while, too- I know we were using them 10 years ago on a development project.  Likely they were used before that.  Again, anytime one can come up with a better, and more reliable way is an improvement.

In terms of tuning- turbo speed is more used for upper limits than much else.  Shaft torque can be helpful when doing ECU tuning- far better than having nothing- you can use that to find best spark and whatnot.   Or if you have the space, on road testing with data vs. a dyno is good.  Of the two, I think the non-contact and cheap torque sensing would be the most useful.  (better is live in cylinder pressure)

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