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Old 03-14-2018, 09:54 AM   #1
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New Engine?

I have followed this company for a couple of years

I think they have the best chance at creating the new engines for outboards , as well as trawlers and noisemakers, and jet skis.. Multi fuel.

LiquidPiston

liquidpiston.com/

http://liquidpiston.com/technology/x-engines-diesel/

Anyone have a better contender for the future?
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Old 03-14-2018, 10:39 AM   #2
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That's pretty cool, but seems very much like a Wankle despite their assertion otherwise. At least the mechanics seem similar.

My recollection is that the ultimate demise of the Wankle was the mechanical seal around the combustion chambers. They didn't have the longevity of a piston+piston ring design, nor the sealing effectiveness, and as a result couldn't keep up with emissions requirements.

Maybe material and manufacturing have solved that problem?
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Old 03-14-2018, 11:57 AM   #3
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Very trick, the sealing wipers are on the cylinder housing instead of the rotating "piston" like they are on a Wankle. This design may last longer, did not see where the side sealing was placed. I wonder too about emission compliance. I am biased having owned an '86 RX7 👍
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Old 03-14-2018, 12:22 PM   #4
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Quote:
Originally Posted by twistedtree View Post
That's pretty cool, but seems very much like a Wankle despite their assertion otherwise. At least the mechanics seem similar.

My recollection is that the ultimate demise of the Wankle was the mechanical seal around the combustion chambers. They didn't have the longevity of a piston+piston ring design, nor the sealing effectiveness, and as a result couldn't keep up with emissions requirements.

Maybe material and manufacturing have solved that problem?


Mazda solved the side seal problems. I drove two rx7s over 200,000 miles each with no issues.

The real issue is emissions. My recollection is the rotary produced High nitrous oxides. Fuel economy also lagged.
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Old 03-14-2018, 01:41 PM   #5
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Two issues with the design that I see:

Like a Wankel, there must be some lube in the fuel/air to lube the rotor seals. This will doom it where tight emission regs are, much like a two stroke.

And a relatively large surface area exposed to the flame compared to the combustion chamber volume. This is basically why the Wankel had generally poor efficiency. Lots of heat sucked out of the process gas before it can do its useful expansion.

Still neat to see someone out there innovating.
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Old 03-14-2018, 03:27 PM   #6
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My impression is that Ski is right. My 94 RX7 was a fantastically fun care to drive with its dual turbo chargers. However, it was not efficient and burned almost as much oil as it did gas. The rotary engine used oil injection to lubricate the engine combustion chamber and those of us who wanted to prolong the life of the seals would typically add oil directly to the fuel when filling up, particularly if going to run the car hard such as a race.

The concept made for a great car that handled high revs easily and was pretty smooth and quiet. I think something like that would be fantastic for applications like a genset or outboard.
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Old 03-14-2018, 07:26 PM   #7
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Check out the 6 stroke engine development. The sixth stroke is water injected into the hot compressed cylinder, it becomes steam advancing the piston, a by product is the steam sucks the heat out of the engine so raw water cooling becomes unnecessary. Makes the engine 20-30% more efficient.
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Old 03-15-2018, 06:18 AM   #8
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I think the LP engine will be first used bu Unkle as a drone engine with multi fueling and probably hand launching.

As it progresses to a vehicle the use of DEF (diesel exhaust fluid) to clean to whatever standard the Air Police demands is now fairly common.

The larger surface area exposed to combustion gasses will need to be addressed by the DEF.

With some refinement a 100HP rated diesel might weigh 50-60 lbs , so a spare engine on board might simply be exchanged in 10 min or so.
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Old 03-16-2018, 05:14 AM   #9
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Also a super short combustion stroke dosen't help the wankels emissions or fuel efficiency. I think mazda is actually brining back a direct injection version of it as a generator for a hybrid.
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Old 03-24-2018, 05:58 PM   #10
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Very interesting engineering, lots of challenges though, the EPA may be more willing to bend under the current administration. (I keep looking for positive things to say about that)
I had a RX2 in the eighties, looked like a sedate Datsun sedan, but could blow the doors off of Camaros and Mustangs!
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