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Author Topic: Petter torque curves and fuel consumption figures  (Read 6517 times)

starfire

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Petter torque curves and fuel consumption figures
« on: October 22, 2016, 09:05:02 PM »
Were there any graphs ever published giving this information?
Can I simply assume a Petter AV2 will be twice the power of an AV1, and if so, would the torque curves match, or does two cylinders make it completely different? Just wondering as I weld up the support frame to accept either engine and ancillaries.
 Im also curious as to where the crankcase breather is on the Petter, the crankcase pressure seems excessive and wondering if its blocked? T Lister used a flapper valve to create negative case pressure, the Petter  doesnt seem to have anything similar?

thanks....

dieselgman

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Re: Petter torque curves and fuel consumption figures
« Reply #1 on: October 22, 2016, 09:52:39 PM »
Petter typically provided much more thorough and polished documentation and research than Lister did. Lister treated much of their stuff as trade secrets. Just an outsider's subjective observation... could be wrong.

 I will pull the AV books when I get the chance. You will likely produce slightly more than double the horsepower and torque with a twin vs a single of the same overall design.

dieselgman
Ford Powerstroke, Caterpillar 3304, Cummins M11, Too many Listers to count...

buickanddeere

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Re: Petter torque curves and fuel consumption figures
« Reply #2 on: October 22, 2016, 10:16:30 PM »
.45lbs of fuel per Hp per hour is about as good as it gets for engines of that type at full load. anything under .40 is goo in a larger more modern engine and iirc 0.38 is exceptional. 

starfire

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Re: Petter torque curves and fuel consumption figures
« Reply #3 on: October 23, 2016, 02:24:41 AM »
Thanks...
I am curious as I noticed when I connect the water injection, within seconds, the engine smooths out and actually closes the rack slightly, suggesting an increase in power with less fuel. Id like to  measure this against the Petter consumption figures if I could. The Lister also had water, though in her case, she didnt visibly/audibly  change with or without, other than eliminating knock.  Im trying to optimise   the water quantity before making a permanent job of it. Right now, its gobbling around 20 percent water to fuel... and seems very happy with this.   After 40 hours run time, there is no signs of condensate in the oil, so maybe Im over thinking it?
 Ill measure fuel consumption /hr and see what i get.
Today the exhaust had a definite aroma of hamburger and chips....  noticed the dog salivating at one point there......  :)

dieselgman

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Re: Petter torque curves and fuel consumption figures
« Reply #4 on: October 23, 2016, 06:50:07 AM »
There is not a lot of data for the AV model. I found a power rating of 3bhp at 1000rpm, 4bhp at 1200rpm, 5bhp at 1500rpm... and that is rated "per cylinder". So, they figure exactly 2 times the power and 2 times the fuel consumption for a twin over a single. That makes good sense to me.

dieselgman
Ford Powerstroke, Caterpillar 3304, Cummins M11, Too many Listers to count...

starfire

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Re: Petter torque curves and fuel consumption figures
« Reply #5 on: October 23, 2016, 09:09:54 AM »
Thankyou DG.  it sounds like a fairly straight power curve, so I guess running it at 1500 is the right thing to do, rather than labouring it at lower revs. I will choose my pulleys accordingly, 1:1 will be perfect. 
One more question, what is the oil pressure roughly?
The reason I ask, I noticed an oil pressure switch  under what appears to be the oil pump housing in the cranking end below the front cover. The switch is faulty, so would like to replace it with something. Will one off a car engine be OK..... I think these switch at around 12 psi? Id  like to wire this up to a warning  buzzer of some sort.

And Ed, Your electric fan idea works great. Just used the one heat sensor thingy in the top of the radiator, fan cycles every few minutes then shuts down.  Ill install another sensor in the bottom to share the buzzer alarm with  the oil as above.

dieselgman

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Re: Petter torque curves and fuel consumption figures
« Reply #6 on: October 23, 2016, 10:45:13 AM »
The power ratings continue on upwards but relative gains drop rapidly - 6hp at 1800rpm, and 6.5hp at 2000rpm. Somewhere between 1200 and 1500 looks like a sweet spot for horsepower. The torque developed probably follows that same curve pretty closely would be my guess.

AV oil pressure is listed at 35psi. Minimum is not given but many similar engines are common at 10psi cutoff.

dieselgman

« Last Edit: October 23, 2016, 10:48:17 AM by dieselgman »
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buickanddeere

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Re: Petter torque curves and fuel consumption figures
« Reply #7 on: October 28, 2016, 02:31:37 AM »
Peak efficiency occurs at or near the same rpms that produce peak torque.