Tuesday, February 17, 2009

Engine telemetry

Main Engine TelemetrySo here's a first glance at a chart of my main engine temperatures with the engine running - very exciting (for me anyway).

I've only connected three temperature sensors, as this is still in development. I didn't want to go mad and connect up much more, only to find there was some kind of problem.

Oh, and I'm also still deciding where to physically locate the rpm sensor, so that data's not shown at the moment.

The engine was idling at a steady 230 rpm for the time shown on the graph, while the seawater inlet temperature was six degrees.

The freshwater inlet and outlet temperatures you see on the chart are the same because the thermostat, which then starts the seawater cooling the fresh water, has not yet opened.

By way of explanation, the main engine, and turbo, is cooled with freshwater, this freshwater is, in turn, cooled with seawater. It's done like this so no corrosive seawater ever gets into the main engine itself. Seawater also cools the inlet air from the turbo, the engine oil and also the gearbox oil, hence the steady rise of that temperature.

I am somewhat surprised to see the temperatures flatten off at thirty odd degrees, but the thermometers on each of the cylinder heads corroborate this, so I know my engine temperature sensors are working properly. The engine is, I suppose, doing no real work, so is likely to stay relatively cool.


  1. Anonymous2:36 PM

    The "fresh water" coolant -- is this typical engine coolant, with ethylene glycol and all that good stuff in it?

  2. I wouldn't drink the stuff.

  3. Great job Tim!

  4. You are a clever man.

    To quote Wrex Tarr, "Ena kuna maningi watches. Kabanga ena Swiss made, I'm not sure!"

  5. Thanks Rob

    More to come on this front...

  6. Hi Paul

    Thanks - most of this is just common sense, so far.