Big Old Diesel engine -- Measure RPM

Hey all, I have a project I am working on that links the old and the new. I have an EMD 64 diesel engine, yes, its a huge old locomotive engine. Bascially, I want to measure the RPM of the motor, and based on the RPM, control a valve actuator to allow a proportional amount of airflow through the valve. When the RPM peaks, I want the actuator at a full 90 percent, and then at idle, down to 0.

The engine, being as old as it is, does not have all the modern interfaces, but people have built crankshaft sensors for the engine. I am open to purchasing an off the shelf crankshaft sensor and valve actuator, but i think the link between them will likely be an arduino board (or something of the ilk). Anyone have some sage advice for me?

thanks!

Wow, that’s some serious hardware! 3000 HP or so? How many cylinders?

Have you researched sensors and actuators? Can you provide links to likely candidates? Would you also mind describing what the valve actuator controls? Sounds like an air valve, but what is the air for?

RPM should be straightforward, the valve may require some interface circuitry, assuming it’s big like the engine, it’ll probably require more power than a microcontroller can provide directly.

Plenty of people have implemented rpm measurement with magnets and hall sensors - try searching the forums. What does the airflow valve do? How would you control it?

crikey what are you going to do with it!?

Make sure you still have mechanical overspeed protection. Below is how I feel some mornings.

now [u]that[/u] is a carbon footprint!

hey all, thanks for the replies (and apologies for the delayed response, was out of town). the engine is a locomotive engine that is being used for large marine applications. the air inlet is a manually controlled valve. here is a doc that basically shows the valve i am trying to control. https://docs.google.com/open?id=1Enx6UIKJbK1BT4D0hRnqkPbdqVBagUF1rKUM6Fn8Evha9XHWkhRhiAJGWwHX

the "air import valve" is the one that i want to control based on RPM. according to the instructions, someone will manually control it now, and that just has far too much room for error.

thanks again for all the great feedback.

man that must be a fun 'toy'!

I can't even begin to conceive how you handle/constrain that much power and weight..

Did you mean EMD 645 series? 645 cubic inches per cylinder? I've worked on the little guys in a factory-authorized rebuilder's shop. 9.0625" bore, 10" stroke. The 16-cylinder version is 10320 c.i. Loved the sound on the dyno - shook the ground a mile away! Neighboring machine shop used to complain that their CNC mills couldn't produce satisfactory finishes while the engines were being dynoed.

Loved the sound on the dyno - shook the ground a mile away! Neighboring machine shop used to complain that their CNC mills couldn’t produce satisfactory finishes while the engines were being dynoed.

Sounds like a critically out of balance or misaligned engine setup.

Mmmmmm EMD's make one of the world's most beautiful sounds!! Long live big old diesels!! :grin:

If you search McMaster-Carr for “electrically operated ball valves” you’ll get an idea on the price range. Belimo has decent online documentation on their valve retrofit kits. They have either a PWM or 0-5V option for controlling the valve so it should be straightforward to interface.