“Super Engine” may fundamentally change the way internal combustion engines work

Re:“Super Engine” may fundamentally change the way internal ... by djcjcjdhc on Thursday February 25, 2016 @05:51PM (#11178487)

Most IC engines are nowhere near the carnot limit, which is around 60%-70% in most cases. The majority of the efficiency losses come from excessive heat rejection in the engine block and also mass transfer in the exhaust. Most engine blocks are (in)conveniently made out of aluminum, which has a very high thermal conductivity, meaning more energy gets transferred to the cylinder walls and wasted during combustion.

As a mechanical engineer, this engine design seems much more promising, however: http://liquidpiston.com/

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Re:“Super Engine” may fundamentally change the way internal ... by Grishnakh on Friday February 26, 2016 @02:00PM (#11183261)

Engine blocks used to be made of cast iron, but they've pretty much all moved to aluminum because of 1) weight, and 2) that higher thermal conductivity. IANAME, but IIRC the problem with iron's lower thermal conductivity is that it created hot spots which could cause pre-ignition, so you had to use lower compression ratios to avoid this. Aluminum has more uniform temperature so you can boost the compression ratio, which gets you more efficiency and power.

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