"0% interest rate"
You're refering to Japan, right?

You're right, hyperinflation sounds so *easy*, but...

Please explain how to add money to the system in order to create price inflation (central bank / treasury). Why isn't it working right now?

Where did your $MONEY come from to multiply with inflation ($N)??

Fiat is not Fiat, meaning, it is not just "printed" without obligation. Instead, it is "borrowed" into existence. In the (Central Bank's) books "new" money looks like this:
Debit = Credit

Looking at your equation let's define:

$MoneyB + $NewDebt = $MoneyA + $NewMoney

Now, like a good Enron, wie act like we don't have any debt or say that our debt is part of the economy too and redefine: $MoneyB = $MoneyA + $NewMoney + $NewDebt, which will end in bankrupcy if there's no wealth behind that new debt. But that's not our question right now.

What we like to do in our economy is forget that the new debt ever has to be paid back:

$MoneyB = $MoneyA + $NewMoney

If this were the case, then inflation would be easy to produce. Then your equation could make sense. But what's happening now is not only new debt but also "deleveraging" ($DebtRepaid) and/or "defaulting" ($DebtDefault). Meaning:

$NewMoney = $NewDebt - $DebtDefault&Repaid
meaning:
$MoneyB = $MoneyA + $NewDebt - $DebtDefault&Repaid

Which tells me that inflation will ONLY occur if we make more debt than what is being defaulted and deleveraged.

Or is there a fault in my logic?

Cheers, Dom