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Inverter and travel pack

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1 minute ago, cuthound said:

 

Interesting, that 2008 engine is still using a Woodruff key to secure the pulleys, yet my 2007 Beta uses the splined crankshaft extension to drive the pulleys.

 

I wonder if their engine was "old stock" when fiitted? Or perhaps the build time was exceedingly long?

We know some Hudson owners with a 2009 engine with the splined crank, that had this problem. So I think the splines only reduce the problem, they don’t entirely fix it.
Even without a TP the 175A alternator can put a pretty big side force on the pulley at Idle, so we are always careful to avoid big electrical loads at idle.

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5 minutes ago, nicknorman said:

We know some Hudson owners with a 2009 engine with the splined crank, that had this problem. So I think the splines only reduce the problem, they don’t entirely fix it.
Even without a TP the 175A alternator can put a pretty big side force on the pulley at Idle, so we are always careful to avoid big electrical loads at idle.

 

Yes that's what I do. Basic mechanical sympathy. Never let an engine labour or hold it at the red line! 😁

 

I guess lithium batteries will exacerbate this problem as the domestic alternator will spend a lot longer a high loads than one with lead acid batteries?

Edited by cuthound
To add the last paragraph

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I am also reminded that both the TP and the 175A alternator on our boat have freewheeling pulleys. Not sure when they came in but I think that also helps to reduce peak loads by reducing the transfer of torsional oscillations.

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1 hour ago, nicknorman said:

I am also reminded that both the TP and the 175A alternator on our boat have freewheeling pulleys. Not sure when they came in but I think that also helps to reduce peak loads by reducing the transfer of torsional oscillations.

There is a theory that these things can actually make the situation worse by introducing an impulsive "snatch" everytime the pulley re-engages with the engine, though until I see any evidence of this I will put it in the boater urban myth category, along with batteries self destructing at 49%.

 

We have the JD3 which has huge torsional displacements at low revs, and no free wheel on the alternator or TP. The TP belt makes a little squeak when loaded hard due (I assume) to tiny slips on every reversal. I can only fix this my over-tightening the belt but don't want to. Have done 14000 hours with only one belt change so it must be ok. Trying a freewheel pulley would be very interesting and its somewhere on the todo list.

 

..................Dave

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3 hours ago, dmr said:

There is a theory that these things can actually make the situation worse by introducing an impulsive "snatch" everytime the pulley re-engages with the engine, though until I see any evidence of this I will put it in the boater urban myth category, along with batteries self destructing at 49%.

 

We have the JD3 which has huge torsional displacements at low revs, and no free wheel on the alternator or TP. The TP belt makes a little squeak when loaded hard due (I assume) to tiny slips on every reversal. I can only fix this my over-tightening the belt but don't want to. Have done 14000 hours with only one belt change so it must be ok. Trying a freewheel pulley would be very interesting and its somewhere on the todo list.

 

..................Dave

It seems to be the case that modern cars all have freewheels in the alternator. I am unsure of the exact benefit but suspect it is more to do with what happens when the alternator is lightly loaded - the engine suddenly slowing down on compression stroke doesn't force the alternator to slow down. Whereas when the alternator is heavily loaded as soon as the drive is removed (engine slows down) the alternator will slow down of its own accord due to the electro-mechanical load. But I am just hypothesising!

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22 minutes ago, nicknorman said:

It seems to be the case that modern cars all have freewheels in the alternator. I am unsure of the exact benefit but suspect it is more to do with what happens when the alternator is lightly loaded - the engine suddenly slowing down on compression stroke doesn't force the alternator to slow down. Whereas when the alternator is heavily loaded as soon as the drive is removed (engine slows down) the alternator will slow down of its own accord due to the electro-mechanical load. But I am just hypothesising!

I remember all this happening but can't remember all the details, might be getting old, or maybe more interested in boats than cars these days.  Ever bigger alternators and the use of slightly slower tickovers (to save fuel) were factors, but the big one was the introduction of those awful dual mass flywheels. These were another fuel saver, or more a response to the slower tickover and thinner gearbox oil fuel savers. In effect they are a much smaller flywheel on the crank itself so give much bigger crankshaft torsional displacement (rigid body, not actual bending) and these really messed up the "FEAD" (front end auxiliary drive or belts!). The freewheel pulley was a solution to this, sometimes together with an isolated front pulley/damper. I spent a lot of time producing instrumentation to measure/solve these problems. Boat engines have nice big solid flywheels which are much better.

I suspect if engineers had thought through all the consequences they would not have contemplated dual mass flywheels, but having invested so much effort in them there was no turning back.

 

.................Dave

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9 hours ago, cuthound said:

 

I wonder if their engine was "old stock" when fiitted? Or perhaps the build time was exceedingly long?

The build time is in the Blog but I have a slow connection tonight

 

4 hours ago, nicknorman said:

It seems to be the case that modern cars all have freewheels in the alternator. I am unsure of the exact benefit but suspect it is more to do with what happens when the alternator is lightly loaded - the engine suddenly slowing down on compression stroke doesn't force the alternator to slow down. Whereas when the alternator is heavily loaded as soon as the drive is removed (engine slows down) the alternator will slow down of its own accord due to the electro-mechanical load. But I am just hypothesising!

Isn't that how the stop start thing work on modern cars, Just what I have heard, not done any research

 

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