LiquidPiston X Mini 70cc Engine

[betasniper]

Originally Posted by NeilBlanchard

The rotor is the valves and the combustion chamber all in one. It is a 4 stroke engine, but there are three combustion events per revolution of the rotor.

Technically true, But the output shaft rotates at twice the speed of the rotor so it is actually still equivalent to a 3 cylinder engine. (3 combustion events every 2 revolutions). Still a nice idea. Could be great as a 2 rotor(6 cyl equivalent) for a regular car.

[user removed]

Bullets and pistons are round for a reason. Highest volume for surface area, mating surfaces expanding and contracting at the same rate. Easy to seal and long lasting.

Now get rid of the reciprocation costs, valve train costs and minimize the heat losses to the cylinder head and manifolds by using the exhaust to preheat the intake, combined with a single injector and inlet port for combustion events and you're speaking my language.

regards
mech

[betasniper]

A Theoretically Ideal engine would likely be a expandable spherical chamber but I am not sure how that would work. Circles are easier to seal with a back up compression ring, but this engine doesn't seem to have the traditional problems of a wankel seal because the sides of the apex seal can butt up against the side walls of the housing.

Old Mechanic: Could you tell me which frame (or second) in the 14sec video you see the pressure opposing rotation? I'm pretty sure regular piston engines also ignite the mixture before TDC by about 30° of crank rotation which also tries to oppose the crank.

[jakobnev]

It's a bit ironic perhaps, but things that work tend to be invented once, things that don't however..

[IamIan]

Originally Posted by NeilBlanchard

They have tested it at 3HP on the dynamometer For a 70cc engine.

FYI ... AFAIK this is just the most recent 'version' prototype ... sense the company founded back around ~2004 ... They have had other prototypes of earlier versions... As I recall , there is a SAE paper from ~2010 on a 20HP 140cc prototype ( the "M2" )

Link

Previously, LiquidPiston has demonstrated proof-of-principle 70 and 40 HP engine prototypes (X1 and X2) that are capable of running for a short time at light load, and demonstrate compression ignition of diesel or JP-8 fuel, and net indicated efficiency of 33% (at light-load)

I'm wishing them the best for more improvements in the future.

[NeilBlanchard]

So, it lacks all the parasitic losses of a reciprocating engine with poppet valves, but it may be harder to seal.

We will have to see how they proceed from here.

[cRiPpLe_rOoStEr]

I wouldn't really hold my breath for a rotary engine, but it could become a reasonable option for the general aviation if it can overcome the durability issues that have always plagued the Wankel design.

[Fingie]

isn't rotary pretty reliable in constant-rpm applications?

[cptsideways]

The big difference with this and the Mazda one is the piston does not rotate it oscillates so much simpler to seal

[cRiPpLe_rOoStEr]

Originally Posted by Fingie

isn't rotary pretty reliable in constant-rpm applications?

Had them been reliable at all, don't you believe they would have taken over the stationary/industrial market already?