Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

stillsearching · 08-31-2012, 05:17 AM

I was thinking the other day...

Doing some searches here about hydraulic hybrids, I haven't searched yet for pneumatic hybrids but I imagine things are somewhat similar.

Sole point of a hybrid is using braking energy to accelerate again, not to cruise the car. Several ways to do that.

One advantage of using "pulse and glide" is from what I understand to keep the engine where it is more efficient? Ie - to add energy (increasing speed) while the engine is in a moderate load more efficient state of peak BSFC, then to shut it off completely and coast for a bit, then to restart and accelerate back up again. Almost like a flywheel effect except you are storing energy in the moving car itself. Downsides include other drivers wondering WTF you are doing, higher aerodynamic resistance and exceeding speeding laws at the higher speed you obtain, annoying drivers and needing driving conditions that even allow it.

But why couldn't that be done internally?

I was resuming an old conversation about flywheels in one thread, and another about hit and miss engines in the other thread being a poor way to store energy...

What if a hybrid system were designed that, instead of solely storing energy during braking for acceleration, it stored energy from a pulse of power from the engine?

What if that let you stay a nice slower speed, 50mph or whatever you wanted (or 70mph if you needed to) being able to be used in close in traffic, no annoying other drivers, etc.

What if instead of pulse and glide making the vehicle accelerate and decelerate you simply used the engine on mode to add energy to a battery pack, or pneumatic/hydraulic accumulator, and then shut off the engine, bleeding power back out again to maintain speed, then using the last of pressure to kick the engine back on again into a moderate load condition?

08-31-2012, 05:17 AM	#1 (permalink)
stillsearching EcoModding Apprentice Join Date: Dec 2011 Location: Minnesota Posts: 201 Thanks: 45 Thanked 8 Times in 7 Posts	Hmm.. hydraulic pulse'n'glide... I was thinking the other day... Doing some searches here about hydraulic hybrids, I haven't searched yet for pneumatic hybrids but I imagine things are somewhat similar. Sole point of a hybrid is using braking energy to accelerate again, not to cruise the car. Several ways to do that. One advantage of using "pulse and glide" is from what I understand to keep the engine where it is more efficient? Ie - to add energy (increasing speed) while the engine is in a moderate load more efficient state of peak BSFC, then to shut it off completely and coast for a bit, then to restart and accelerate back up again. Almost like a flywheel effect except you are storing energy in the moving car itself. Downsides include other drivers wondering WTF you are doing, higher aerodynamic resistance and exceeding speeding laws at the higher speed you obtain, annoying drivers and needing driving conditions that even allow it. But why couldn't that be done internally? I was resuming an old conversation about flywheels in one thread, and another about hit and miss engines in the other thread being a poor way to store energy... What if a hybrid system were designed that, instead of solely storing energy during braking for acceleration, it stored energy from a pulse of power from the engine? What if that let you stay a nice slower speed, 50mph or whatever you wanted (or 70mph if you needed to) being able to be used in close in traffic, no annoying other drivers, etc. What if instead of pulse and glide making the vehicle accelerate and decelerate you simply used the engine on mode to add energy to a battery pack, or pneumatic/hydraulic accumulator, and then shut off the engine, bleeding power back out again to maintain speed, then using the last of pressure to kick the engine back on again into a moderate load condition?