Quote:
Originally Posted by RedDevil
Wow. First, joule is a measure of energy in itself. A certain mass moving at a certain speed has energy in the form of momentum that can be expressed in joules.
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Joules are a measure of energy yes.
Momentum however is not the same thing as Kinetic Energy ... Momentum is not measured in joules ... Kinetic Energy is... although both relate to a moving body , they are not the same thing.
Quote:
Originally Posted by RedDevil
The energy you have to invest to accelerate is gained back when coasting as the engine would have to run when maintaining speed.
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Nope.
It is not a 100% efficient system.
Weather you input joules of energy to maintain a given average speed constantly or you input joules of energy in pulses it net the same average speed ... either way you must input energy... but the varying speed always costs more energy to the same average speed and otherwise same conditions.
Quote:
Originally Posted by RedDevil
Changing speed does not change the total amount of energy, just the state of that energy.
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nope.
Going faster takes more energy to cover the same distance.
A fluctuating speed takes more energy to cover the same distance at the same average speed and conditions.
Quote:
Originally Posted by RedDevil
When you P&G the difference between highest and lowest speed does not need to be so big that air resistance plays a mayor role. The speed would be low anyway. It pretty much evens out.
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Any variation in speed results in more joules of energy being used.... even 0.000001% variation.
Quote:
Originally Posted by RedDevil
It is not my invention. P&G is a well-known and proven way to save gas. Check the hypermiling tips.
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As I said above ... I'll repeat again here:
Quote:
Originally Posted by IamIan
Sometimes the additional joules of P&G vehicle are countered by enough increase in ICE P&G efficiency ... sometimes not ... like many things it depends on the specifics.
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I think it is more useful to understand how it works ... both the good and the bad ... then one is more able to maximize the good aspects , and minimize the bad ... pretending the bad doesn't exist is not useful.