ICE ICE BABY (engines of the future)

Lotus Omnivore engine
http://jalopnik.com/5454636/lotus-om...ively-animated

This is an HCCI engine that can use a variety of fuels. The VCR puck is sort of a big deal. Check out the monoblock head. Boost please?

Ricardo 2/4sight engine
http://www.ricardo.com/en-gb/Enginee...ge=en-GB&tab=1

This engine promises to switch between 2-stroke and 4-stroke on the fly. That bumps up the low RPM torque that is usually a problem with small turbocharged engines.

Ilmor 5 Stroke engine
http://www.ilmor.co.uk/concept_5-stroke_1.php

The Ilmor engine uses nothing more than conventional technology and steam engine-type power recovery. This engine could easily go into production. The thing that I like about it is that the additional cylinder would act to muffle the exhaust pulse. Add a turbo and cats to the engine and you wouldn't need a muffler at all.

The last one is interesting. I'm having a hard time understanding how it gains efficiency...isn't energy wasted expelling exhaust gases from the spare cylinder, essentially for the second time? Wouldn't this be equal to the energy gained from the gases entering the cylinder? Is there some sort of energy gain because the gases are still expanding when they enter the third cylinder?

Yeah, it's basically the same exhaust energy that gets used to spin a turbo (or PRT in old military aircraft). Look at old steam engines for a good explanation. It sounds like the additional cylinder friction and flow restriction due to more poppet valves is less than the amount of energy recovered. Plus, intake and exhaust compression ratios are decoupled. So the mechanical compression ratio can be sky high.