Engine testing 2

[enginesrus]

I just read a story about a fellow visiting a plant that manufactures automotive engines, and he mentioned one of the engines on a dyno has run redline for 5 months nonstop, anyone else have some stories?

 

[dgallup]

We always had a "throttle" control in the control room and could also shut off the fuel supply remotely but that would take awhile to actually stop the engine and was frowned upon because you would have to bleed all the high pressure lines to the injectors to restart. One of the best ways to stop a runaway diesel is a board over the air intake but we never had a remote way to do that. Some diesels when they torch a piston can keep running on their lube oil. Stopping that requires blocking the air. I've seen rags and coats fed into runaway diesels to shut them down.

When I was working on a 1000 cu in V8 diesel development project the head of the injection system group decided it would be a good idea to start an engine that had the governor removed. He was going to hold the fuel racks (the pump was a little V8 the lived in the engine V) with his hands. It started OK but when he lost his grip it started to run away. Fortunately another engineer was able to feed his lab coat into the turbo inlet and get it stopped.

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[CWB1]

Ahhh, the "good old days." Today we have multiple safeties on every system with computer controlled limits to shut them down individually, as well as a control on the dynos to expedite stopping engine rotation. The operator doesn't have to respond to engine issues unless he wants it to keep running, which in many cases actually causes more issues as overridden safeties lead to damaged rather than shut-down engines.

 

[catserveng]

I ran and then oversaw operations of our dyno's and test cells mid 80's until 2000, not only did we dyno our own brand engines, but we had a "certified" dyno and test cell for military work, so we saw a lot of other manufacturers engines come thru our cells as well.

A lot of engines we got for the bob tail dyno were what we considered "bare" engines, minimal accessories, and a lot of times no air cleaners, exhaust piping, fuel filters, etc. Especially on marine engines, few engines had any means of shutoff other than a mechanical lever, if we could make it work we had a assortment of cable ran into the dyno operators station. If the engine had an air dam installed on the sir inlet system we also had cables for then as well. We did add a "dump bottle" CO2 fire system aimed at the air inlet that worked most of the time.

Testing older design engines was interesting work, took a lot of time to get them in the cell and hooked up to meet the testing needs, while our internal failure rate on dyno was low (didn't have failures very often but they did occur), we did get a lot of failures on "test only" engines repaired by other facilities. So got to see a lot of scenes like the one from the you tube video above. I can also tell you while it looks like there was plenty of time to respond to the failure shown above, operating a dyno like that had a lot going on,and options for remote "fast" shutdown were limited.

As CWB1 noted above, newer engines have LOTS of built in protections, when we first started dealing with electronically controlled engines in dyno testing we had to jump thru a lot of hoops to actually get them running and up to load, as systems got more complex the engine ECM was looking for other controllers input or permissives to go to rated speed or load up. Many engines now have a "dyno mode" setting in the ECM that allows you to override a lot of the safeties so you can test a bare engine, but access to that feature can be pretty limited.

MikeL

 

[gruntguru]

Hard to beat Halon gas if you need to stop an engine. Health and environmental concerns are severely restricting its use these days.

je suis charlie