Toyota Describes Combustion Engine That Generates Electricity Directly

cartechboy writes: "While electric cars are now more available than ever, combustion engines will remain for decades to come. Now auto engineers are working to refine combustion power as part of cars that are increasingly electrified, including plug-in hybrids. Toyota's new 'Free Piston Engine Linear Generator' (or FPEG) shows us one potential way. Linear engines eliminate the rotating crankshaft of conventional engines in favor of a single chamber, in which a piston moves forward and backward. A linear engine has no crankshaft, nor connecting rods. In their place is a gas-filled chamber, the compression of which functions like a spring — returning the piston after the expansion / combustion phases of a typical combustion cycle. This back-and-forth motion can be turned into energy, when you haven't got a crankshaft and the mechanically-useful rotation it produces. While linear engines are far from new, and Toyota's test units are only 10 kW (13 horsepower), a pair of them can still produce enough electricity for a Yaris- or Corolla-sized vehicle to cruise on the highway at 75 mph."

Re:Efficiency?

[Todd Palin]

I was thinking the same thing. Efficiency is the real question. I assume the article would have mentioned this if the efficiency was available to the authors. The fact that efficiency figures weren't available means they were not very impressive at this stage. The devil is in the details.

Re:Efficiency?

[Anonymous Coward]

Turbines are really not efficient at all. Even if you made a perfect turbine, the Brayton cycle is inherently less efficient than the Otto/Atkinson cycle used in internal combustion engines.

They are used in airplanes because nothing beats their power/weight ratio, and in power plants because of their longer MTBF and ability to burn lower quality fuels.

Re:10 kw

[supercrisp]

And it won't be cheap for long in the US. The natty gas industry is lobbying for it to become a "foreign policy tool." They want to ship it across the sea, somehow making it cheaper on the European market than Russian gas. I wonder who'll end up subsidizing that? The struggling US economy, or the almost bankrupt European economies, or Germany?