Wednesday, June 30, 2010

Engine temperatures

Engine temperaturesAs promised, here is the engine telemetry from Saturday's run. I understand this will not fascinate everyone.

Overall, I believe that if I keep these kinds of records, and compare back to them, I'll be better placed to spot issues long before they get out of hand and cause a problem on board.

The top chart shows the RPM, while the bottom chart, on the same time-line, shows the engine temperatures for various key points.

The big dip and zigzag in revs you can see just before 10.00 is John cursing some yachtie or other who crossed us!

The revs zigzagging at 10.18 is John manoeuvring Lady Jane across the Itchen, so we can pick up our mooring. From 10.25 Lady Jane would have been moored up and we would have been concentrating on getting those lines snug.

The red and blue lines represent the cooling freshwater which is circulated through the engine, while the green and purple lines represent the salt water which is pumped through the boat cooling the freshwater on it's way.

The warmer the engine gets the more a thermostat opens, allowing the salt water to increasingly cool the freshwater. The thermostat is adjustable.

The salt water also cools the turbo, so will always show a rise in temperature even if the thermostat is not opened.

Looking at the diverging of the blue and red lines, and the raw data, it seems to me the thermostat starts opening at about 56 degrees, at about 10.15, the revs drop after that so the engine then cools somewhat.

We definitely need a longer trip, and the missing pressure data, to give a better overall picture of the engine's performance.

The good news is the issue on the new circuit board is fixed, so next time we go out for a spin I should also be able to show pressures.

9 comments:

  1. Tim,
    I am one of the people that enjoy looking at things like that and anything mechanical.

    Bill Kelleher

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  2. Charts are a great way to get a visual on what is happening. They're a great tool to use in an after action review or in this case post sail.

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  3. Anonymous9:41 AM

    maybe you should fit the skipper with sensors?

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  4. Anonymous11:11 PM

    A cruise to St.Anthony should straighten everything out in your electronics department...come over for a visit.Tony R.

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  5. Anonymous2:07 PM

    Interesting the salt-in temperature seemed to rise steadily. Also you have very warm water there -- 22C is what I would expect seawater to be in Montego Bay, not Southampton.

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  6. Hi Anonymous

    I suspect any sensors attached to the skipper would have blown up as we made that turn in the river, just before the rib started pushing!

    Cheers

    Tim

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  7. Hi Tony

    That's something to work up to, but sounds good :)

    Cheers

    Tim

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  8. Hi Anonymous

    I noticed that, and put it down to us turning into the Itchen, which may well have been warmer than the River Test.

    The temperatures are reasonably accurate, today I see that Bramblemet, in the Solent, is reporting sea temperatures of 19.3C

    Cheers

    Tim

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  9. Anonymous11:45 AM

    Test

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