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Absolutely true Mike, I referred to that situation in the post, and to a point you could increase the accumulator size or maximum pressure.
Of course when comparing the electric to hydraulic efficiencies, you also have to understand the downhill distance would have to be 3 times longer to recapture the same amount of usable energy with the electric hybrid.
Batteries take many times longer to accept the same amount of energy as they can apply to the vehicle, while hydraulics do not care whether it is applied or recovered.
A good example is the electric drag racer (Datsun 210) in another thread on this forum that does 10 second 110 MPH 1/4 mile runs. It takes almost 20 minutes to recharge the batteries after a 10 second run.
Now Imagine what an all wheel drive drag racer would do if you had only enough accumulator for a single 1/4 mile run. I guarantee you it would be a whole lot faster than the Datsun, with all 4 wheels pulling at the limit of their traction. The problem would be its weight, which would be considerably lower than the electric drag racer, even if you used a 20-30 gallon accumulator. In fact you might have to add ballast to get better traction.
I hypermile my CVT Insight, using P&G I found that you can accelerate very gradually or climb a very slight hill. Rate of acceleration is measured in 1 MPH per every 3 or 4 seconds. The instant mileage reading changes very little when you are accelerating, but when you get to your target speed and let off the gas just a little more in the deceleration direction you can see mileage jump to between 125 and 150 on the instantaneous bar graph. The speed differences are very small and most other drivers do not realize what you are really doing, compared to P&G in my Echo.
I have managed 70.2 with the CVT Insight for 655 miles on one tank at highway speeds averaging 57 MPH. This week my daily (40 mile trip) average was 75 MPG. Best day was a 19 mile run at 84.1 MPG. Average speed was 36 MPH overall, timed from beginning to end of the run, 19 miles in 32 minutes.
The point is when you hypermile a gas electric hybrid, you are not really using the engine to store the energy to apply it later to the power train, like in traditional P&G as I understand it.
That is because the increased engine efficiency is more than offset by the losses in conversion and reapplication as demonstrated in the comparisons in the photos.
regards
Mech
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