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A comment on San Antonio man has engine that gets 100 mpg.

Re:San Antonio man has engine that gets 100 mpg by userbinator on Wednesday June 15, 2016 @10:31PM (#11913553)
This recycling feature boosts the engine's efficiency to a whopping 50 percent. For comparison, a standard internal combustion engine operates only at 14 percent efficiency.

I don't know what a "standard internal combustion engine" is, but 14% is absurdly low. Maybe a Ford Model T would be around there? A glance at

https://en.wikipedia.org/wiki/Specific_fuel_consumption_(sha...

shows efficiencies of ~30% for typical gasoline engines of the automotive type (which agrees with what I remember when I studied this stuff), and closer to 50% for large two-stroke diesels.

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Re:San Antonio man has engine that gets 100 mpg by gameofdrones on Wednesday June 15, 2016 @11:00PM (#11913632)
The most efficient fossil fuel-based engines are massive two-stroke diesels found on extremely large ships and in some peaker power gensets which currently have efficiencies just over 51% and BSFC's over 275.

https://en.wikipedia.org/wiki/Brake_specific_fuel_consumptio...

In this case, he may have matched the performance of very large engines, which have the advantages of optimizing for scale, but time will tell whether this solution can deliver.

[ Parent | on HN ]
Re:San Antonio man has engine that gets 100 mpg by semi-extrinsic on Thursday June 16, 2016 @02:34AM (#11914415)
> The most efficient fossil fuel-based engines are massive two-stroke diesels

Unless you count combined-cycle gas turbines (also found on big ships and powerplants), which can squeeze above 60% efficiency.

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