Liquid Piston? 40Bhp 75% Thermal Efficiency
 

LiquidPiston unveils 40-bhp X2 rotary engine with 75 percent thermal efficiency

http://www.gizmag.com/liquidpistol-rotary/24623/

On paper the otto cycle can be up to 73% efficient (if I remember correctly) so it would be nice to see how this one does in the real world.

Very interesting. Very very interesting. I wonder if it will make it into the production phase? Have seen a lot of "revolutionary" motors stall in the transition to commercial production due to lack of investors and interest.

' In current ICE engines, an alarming amount of fuel goes out the tailpipe. '

I've seen similar statements used to advertise other miraculous advances in technology.

I don't know if it's the manufacturer or the article writer, but it doesn't add any credibility to the product in question.

I agree, they are only hurting them selves.

Count me as a skeptic. Some of the language as pointed above raise red flags as to the credibility of the invention. Why wouldn't the engine be suitable for primary transportation? The article seemed to say it is only suitable as an APU. Perhaps it suffers from poor performance or longevity at varied speeds? If so, then it would be suitable as a series hybrid electric engine.

I think Argonne Labs is approaching 60% efficiency with a mostly conventional otto cycle engine. I think it should be obvious that when you start throttling any engine to control speed in a vehicle, you can forget any efficiency in even half that range, which is why vehicles will neeed high efficiency capacitive energy storage and IVT transmissions to separate the engine from directly powering the vehicle.

Once this is accomplished all energy consuming primary power sources will be able to provide power to drive the vehicle.

regards
Mech

LiquidPiston ::

57% efficient in real life is their goal.

“Everyone would say at first glance that the diesel engine is more efficient (than the petrol engine). The truth is that if you had both engines at the same compression ratio, the spark-ignited engine has a faster combustion process and a more efficient process. In practice, it’s limited to a lower compression ratio otherwise you get spontaneous ignition.”

That is one of the stupidest statements I have read. Duh if you take away the benefits of running diesel the gas engine will be better.

With the lack of detail regarding whats its capable of, RPM rates, Tq isn't even included with the peak 40HP claim. I don't see this as much more than a generator like it steers toward with its description.

Someone mentioned in the gizmag comments about "not being RPM variable friendly" and another saying might "operate within a narrow power/rpm range".

Even if it operates decently within a givin power/rpm range, one could retain the use of the existing transmissions and low gearing for the low RPM variable diesel engine it could replace.

Unlike ICE having a small boost in FE when properly tuned with a turbo, it would be interesting to see the outcome of a turbo model of this "New Cycle" with regards to fuel consumption, heat, peak power/Tq?! ...If it ever comes to light. Maybe I'm over shooting what this engine is capable of though.

...so, which is it that I'm smelling? Unicorn pharts or rainbow-colored road apples?

I'm with ya this one still, but hey if something works(to a degree), then it still works, and still might find a place for itself

Otto cycle efficiency is related to compression ratio. In theory the Otto cycle can get as close to 100% efficiency (but less than 100%) if you run a high enough CR.

If you include the slight advantage of having a larger expansion ratio, 75% efficiency requires a CR of about 30:1, Which I think is going to be expensive to deliver with the durability expected in modern machinery - considering those sliding seals, especially the end down by the axis. Mazda always had trouble with those seals.

-mort

Pistons engines tend to be very good at extracting energy from fuel under lots of different loads and speeds.
Rotating and rotary engines seem to only be better under special conditions.

it's a rotary, it makes a laughable amount of torque at all times, which is why they need to spin them to ridiculous RPM to get "impressive" HP numbers.

it could be used as a normal engine..... but it would require a non-"normal" transmission.... just have the engine idle at a fairly low RPM, then any kind of throttle would spin the engine up to a better point in the BSFC map and have a CVT trans keep the engine at that speed at all times.... but i imagine that would be quite an annoying vehicle to drive. but the same issue would be present as a "generator" engine.