linear generator engine

[arcosine]

A new type of engine for hybrids:

https://www.youtube.com/watch?v=iBwIMl917is

[BrandonMods]

I wonder what the net recovery to recharge the batteries would be from the linear generator.

[freebeard]

Problems include ignition timing, and the 'air springs' generating heat. Here's a solution from Toyota:

Green Car Congress: Toyota Central R&D developing free-piston engine linear generator; envisioning multi-FPEG units for electric drive vehicles

The “W-shape” piston design offers several advantages, Toyota says:

The larger cross-sectional area of the gas spring chamber leads to lower compression temperature of the gas spring chamber and consequently decreased heat loss.

The piston has a hollow structure and moves along a column stay, which in turn enables the construction of a cooling oil passage within the stay. The key technologies to deliver stable continuous operation of an FPEG are lubricating, cooling, and control logic. (The Toyota team’s second paper deals exclusively with the control system.)

The inner periphery of the hollow piston also serves as a sliding surface on the column stay, enabling a steady small clearance between the magnets and coil for improved generating efficiency.

The magnet is set far from the piston top, preventing magnet degaussing by heating.

[user removed]

In the 2006 EPA documents the efficiency of free piston engines was calculated to be 58%.

OMG, A FREAKIN TWO STROKE. YOU CAN'T POSSIBLY GET IT TO PASS EMISSIONS.

A quote from DOE documents sent to me stating that a rotary engine (not wankel) could never be built that would pass emissions in the US.

Google INNAS Chiron, direct hydraulic pressure free piston engine and a drive design with close to 3 times the regenerative efficiency of gas electric hybrids.

So today, when proposed by Toyota, everything is copacetic.

regards
mech

[arcosine]

I like the opposed piston design, less heat loss to the head, well theres no head. Could have a genrenerative gas spring where waste exhaust heat is added near bdc.

[P-hack]

I imagine we might see some microturbines and micro-generators with a fixed power output and much better efficiency (esp with cogen) i.e. ~%60 fuel to electric. I don't know if this is gonna make it into production. As an aside, it is hard to get %93 mechanical to electrical efficiency in a hydraulic pump at 800,000 rpm

https://www.academia.edu/5905748/MIC...RO_GAS_TURBINE

[arcosine]

Constant power turbine not a new idea:

An Electric Car That Hardly Needs Batteries - Businessweek

http://articles.latimes.com/1997/nov...iness/fi-55325

https://www.youtube.com/watch?v=xG66JQmdMv8

Originally Posted by P-hack

I imagine we might see some microturbines and micro-generators with a fixed power output and much better efficiency (esp with cogen) i.e. ~%60 fuel to electric. I don't know if this is gonna make it into production. As an aside, it is hard to get %93 mechanical to electrical efficiency in a hydraulic pump at 800,000 rpm

https://www.academia.edu/5905748/MIC...RO_GAS_TURBINE

[freebeard]

At 0:24 seconds—that thing is/was loud!