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Pinnacle Engines introduces new opposed-piston engine with a promise of 30-50% better fuel economy

Illustration of a three-cylinder configuration of the Pinnacle opposed-piston engine. Click to enlarge.

Startup Pinnacle Engines unveiled plans to commercialize a new, more efficient combustion engine by 2013. The company says the new engine design enables significant reductions in fuel consumption and greenhouse gas emissions without increasing vehicle cost. Pinnacle has raised $13.5 million in venture funding from NEA, Bessemer Venture Partners and Infield Capital.

The Pinnacle engine is based on a four-stroke, spark-ignited (SI), opposed-piston, sleeve-valve architecture. Pinnacle says the engine achieves 30-50% better fuel economy in various drive cycle comparisons without the large cost penalty that can be associated with significant fuel economy improvement. The performance of the Pinnacle Engines design has been independently verified by FEV, Inc., a Pinnacle Engines development partner.

Engines that can deliver significant efficiencies within 5 - 10 years are critical as the global demand for vehicles places a strain on both natural resources and the environment. We believe Pinnacle Engines is in a unique position to have a major impact in that timeframe, by delivering exceptional efficiency gains at the lowest possible cost.

—Rohini Chakravarthy, Pinnacle Board member and a Partner at NEA

The core of Pinnacle’s technology resides in its engine architecture and the new “Cleeves Cycle”. (James Montague (Monty) Cleeves is the Founder, President, and CTO of Pinnacle.) The Cleeves Cycle operates on the Otto cycle (constant volume combustion) or Diesel cycle (constant pressure combustion) depending on operating conditions. Additional efficiency improvements will be realized through incorporation of variable valve timing, direct injection, turbocharging, and Pinnacle’s own low-cost variable compression ratio mechanism.

The result, says Pinnacle, is a more fuel efficient and scalable engine design, and one that is compatible with most fuels including gasoline, diesel, natural gas, propane and their biofuel replacements.

The company is in the process of commercializing its technology through a joint development and licensing agreement with an Asian vehicle OEM. Production is slated to commence in Q1 2013. Further developments, including plans for expansion into the global automotive market, will be revealed later this year.



What? Another one?!?!?!
[rolling eyes]


What do mechanical engineers say?

It seems the opposed-piston engine has been attempted for a 100 years: http://en.wikipedia.org/wiki/Opposed-piston_engine

None the less, http://www.ecomotors.com/ecomotors-internationals-opposed-piston-opposed-cylinder-engine-promises-revolutionize-commercial-ve may be a better investment than some.. http://www.pittsreport.com/2011/01/machines-of-war-blackwater-monsanto-and-bill-gates/


Why is "As a final step before posting your comment, enter the letters and numbers you see in the image below. This prevents automated programs from posting comments." only applied to some comments and have others noted this?


Kelly - I think it happens more often (not all the time though) when you post links...I think it's an anti-spam feature.

Nick Lyons

Not a lot of detail here (or on the company's website), but I'd say Ecomotors design looks more promising. Claims of 30-50% improvement mean nothing, of course. Show me the third-party test results.


Which one will be marketed first, the ESSTor or this ICE?


"based on a four-stroke..
sleeve-valve architecture.."

Sleeve valves are not all that commonly used, it would be good to see the reliability in long term tests with this.

"The [OPOC] engine operates on the 2-cycle principle"

With direct injection this could be cleaner and more efficient than in the past.

Henry Gibson

I have been recommending the OPOC since I first discovered them six or more years ago when they had piston air compressors for scavenging in small sizes, for range extenders for plug in hybrids. FEV was also used to develop and test them. The compression ignition and piston ported valves decreases the complexity. Diesel engines are more efficient and use cheaper to make fuel. New filters and converters can eliminate the particulate problems. Diesel or jet kerosene should be the standard world fuel. Only a slight bit of cleverness would be required to convert older automobiles to burn this fuel if that were needed. But it would be much better to convert natural gas or crude oil or coal into ethanol or methanol for spark engine use.

Single piston automobiles would be more efficient and can be used in hydraulic hybrid designs if only efficiency is wanted. The NOAX free piston hydraulic pump was used in a demonstration hydraulic machine and has be neglected for too long, even by INNAS. It is too bad that INNAS did go find the funding to demonstrate the NOAX in the two commercial PARRY People MOVERS.

Artemis demonstrated the very high efficiency of ordinary automobiles converted to hydraulic hybrids without any engine changes or downsizing which would also increase the efficiency further.

The COMMER trucks with the Rootes engines were well developed, and there may be no reason not to recreate the Pescara free piston gas turbine engines with modern controls and materials. They could burn crude oil.

The Capstone and similar small turbines cleanly burn diesel or kerosene and have sufficient efficiency in hybrid designs, since drivers waste efficiency at high speeds anyway. A five or ten KW Capstone would also be useful for home cogeneration as well as in small automobiles.

Factory produced micro nuclear reactors will produce heat far cheaper than shale gas. A town's own synthetic geothermal energy. ..HG..



Some articles claim a 50% less part count.

What also appears to be a plus is that low power(cruise) can happen by just 'clutching-out' extra cylinder(s), making this a truly variable displacement engine.

Maybe a mix of processor control/new materials/turbos can make this a practical ICE advancement


Talking about vehicle efficiency, the new Japanese SIM-LEI (4-passenger BEV) is a real improvement.

1. Energy consumption = 77 Wh/Km instead of 173 Wh/Km for the leaf and 270 Wh/Km for the Volt.

2. E-range is 333 Km per charge.

3. Acceleration is 0-62 mph in 4.8 secs.

That seems to be the way to go for future longer range higher performance BEVs



The GM Volt is now rated at 225 Wh/Km at 50 Kmh, on flat paved road, no wind, no passengers and no cargo. It is equivalent to 270+ Wh/Km under normal use.


@Henry Gibson: "Diesel engines...use cheaper to make fuel". Not true, its a distillate fuel, expensive and wasteful to refine. Gasoline typically costs less at the pump because its refined by catalytic cracking, a far more efficient process than distillation.
"Diesel or jet kerosene should be the standard world fuel". Impossible because only a small part of a given barrel can make distillate fuels. The demand for distillates is already huge & can't increase without straining supplies.


@ nordic,

Not sure where you got you information, but that's not my understanding.

My understanding is that all crude oil is initially distilled into various fractions that are then further processed into products like gasoline, diesel fuel, kerosene, etc. It doesn't appear that crude is directly run through a FCC (cat cracker).

Furthermore, middle distillate products are more efficiently processed, according to even Toyota, hardly a big diesel proponent (see http://www.mizuho-ir.co.jp/english/knowledge/report/pdf/wtwghg041130.pdf, Tables 2.1.2 – 2.1.4, page 19 [29 of 132]).

According to the GREET model, ULSD is more efficiently processed than gasoline, and the efficiency gap will only widen as crude becomes heavier/sourer.


I thought that they hydro cracked to improve octane, which is another step that requires hydrogen. I remember when they wanted low sulfur diesel, truckers complained that 10 cents more per gallon would break them, but said nothing much when they had to pay a dollar more per gallon on the price run up.


"Talking about vehicle efficiency, the new Japanese SIM-LEI (4-passenger BEV) is a real improvement.
1. Energy consumption = 77 Wh/Km instead of 173 Wh/Km for the leaf and 270 Wh/Km for the Volt.."

If the price is ~ $30,000US - we got a contender. If the 10X faster recharge electrodes are included - we got a BIG winner.


This is exciting if they have a functional prototype running. Until then its a pretty drawing that reminds me of the circular piston engine


Some weaknesses of the Pinnacle engine are:
the sealing, the lubrication and the wear of the sleeve valves;
the cooling of the cylinder;
the lubricant control (the same problem with the two stroke port engines).

The question is:
does the Pinnacle combine the advantages of the four-stroke engines with the advantages of the two-stroke opposed-piston engines, or does it combine their disadvantages?

The four-stroke opposed-piston single-crankshaft full-balanced PatFour engine (at the bottom of the http://www.pattakon.com/pattakonPatPOC.htm page)
uses four conventional poppet valves.

Do you see any advantage of the Pinnacle engine over the PatFour?

Manousos Pattakos


@Henry Gibson:

"Single piston automobiles would be more efficient and can be used in hydraulic hybrid designs if only efficiency is wanted. The NOAX free piston hydraulic pump was used in a demonstration hydraulic machine and has be neglected for too long, even by INNAS. It is too bad that INNAS did go find the funding to demonstrate the NOAX in the two commercial PARRY People MOVERS."

While I was charmed too by the INNAS design, I became less supportive when I read some of their papers. Power to weight ratio seems to be 0.1 kW/kg, about 10 times lower than conventional engines. I know it's an engine in development and they already improved the power to weight ration significantly, but I don't know how much further they can go.


@Manousos Pattakos:

I am very interested in your design and you seem someone who can actually build an engine by himself, which deserves my utmost respect. Do you have a team behind you or any interest of car makers? It is probably quite expensive if it is still all self funded.


For SimonDM:

Thanks. It is self funded.

Even having the car ready for test drives (take a look at the pattakon VVA roller Civic B16A2 prototype having 330 rpm idling and flat torque curve from below 900 rpm to above 9000 rpm, at http://www.pattakon.com ) nobody is willing to try it.
You will not believe how much I have pressed them to take the car and compare it to theirs (Honda, Daimler, BMW, VW, Fiat etc).
As big companies, their snobbery is justified.

In this forum the Pinnacle engine and their bold claims are presented.
Why Pinnacle is not responding to the questions set by the forum members?
Shouldn't the small innovative companies like Pinnacle, EcoMotors, Achates, mce-5 etc be more open to the public questions?

If you like to make a copy of the PatOP or OPRE prototypes, just e-mail me to send you the blueprints.

Manousos Pattakos

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