Transonic combustion 1

[black2003cobra]

Wondered what some of you folks thought about this. (Seems sort of like a combination of HCCI and DI...but different.)

http://www.technologyreview.com/energy/24701/?a=f

Test results seem impressive:

http://green.yahoo.com/blog/ecogeek...n-improves-gas-engine-efficiency-over-50.html

Maybe some of you have seen some other good references?

 

[JSteve2]

Mr. Carnot tells us that there is theoretical efficiency out there to be had (maybe not up to that 50% mark though).

My experience with most of these is that the bad side has been underestimated - e.g. fuel energy reduction due to pre-combustion oxidation, underestimating losses in pre-heating, inability to see gains in transient behaviors as the thing is tuned for a single sweet spot, high dollar catalysts that are unrealistic for production equipment, high sensitivity to catalyst fouling. In this case, they are also dependent upon supercritical fuel injection, making me wonder how robust they will be to fuel formulations that don't meet their ideal lab specifications or to non-ideal ambient conditions. More power to them, so to speak, and we'll see.

 

[SomptingGuy]

The percentages being tossed around are ill defined. I guess the 50% is (up to) 50% better than before, not 50% thermal efficiency. Also, comparing with the highway economy of a Prius is pretty meaningless.

Interesting that the company plans intend to manufacture the engine themselves.

- Steve

 

[YvesLLewelyn]

Usually when I see "revolutionary" engine ideas I immediately think "Oh dear" (or words like that) but this strikes me as not being a bad idea at all - certainly worth trying. The gain in efficiency from reduced pumping losses alone would make it similar to a diesel in fuel efficiency. What CR would the system run at? Maybe they should try a diesel with very hot diesel fuel etc.

 

[black2003cobra]

Out of context, I was assuming they were referring to improvements in brake fuel conversion efficiency, (?f,b = ?m*?c*?t).

Mech efficiency (?m) would go up by eliminating the throttle and associated pumping losses, combustion efficiency (?c) would go up from the lean-burn nature of the engine, and improvements in thermal conversion-efficiency (?t) might result from less heat loss due to lower cylinder temps (such as with HCCI), a higher compression ratio (? not sure), and achieving a much shorter burn duration.

But it was ill defined. More detailed articles/references would be nice. The mileage figures seem pretty good. If anyone comes across any, please post a link. Thanks!

 

[dgallup]

I don't believe they have any intent of building engines, just injection systems. Very few car makers would be interested in buying complete engines and the cost to tool up would be a heavy burden on a start-up. Like most articles, both of those are full on errors like "Once the fuel is injected into the piston" when they obviously mean cylinder.

 

[MikeHalloran]

The 'comparison' between a Prius and a completely different and completely unique vehicle leaves me unable to draw a conclusion, and unlikely to believe anyone else's conclusions.

Better to evaluate their product in a vehicle that's in production, against a hybrid variant that's also in production. There are several such pairs of vehicles now available.

Agreed, the technical content, limited as it is, could use some technical proofreading.




Mike Halloran
Pembroke Pines, FL, USA

 

[black2003cobra]

I checked the USPTO website, and found 3 patents under the company name.

US7,444,230; October 28, 2008
Fuel injector having algorithm controlled look-ahead timing for injector-ignition operation

Abstract:
The present invention provides an injector-ignition fuel injection system for an internal combustion engine, comprising an ECU controlling a heated catalyzed fuel injector for heating and catalyzing a next fuel charge, wherein the ECU uses a one firing cycle look-ahead algorithm for controlling fuel injection. The ECU may further incorporate a look-up table, auto-tuning functions and heuristics to compensate for the rapid rotational de-acceleration that occurs near top dead center in lightweight small ultra-high compression engines as may be used with this invention. The ECU may further ramp heat input to the injector in response to engine acceleration requests and, under such circumstances, may extend its look-ahead for up to four firing cycles.

Inventors: Cheiky; Michael C. (Thousand Oaks, CA)
Assignee: Transonic Combustion, Inc. (Camarillo, CA)
Appl. No.: 11/692,092
Filed: March 27, 2007

US7,546,826; June 16, 2009
Injector-ignition for an internal combustion engine

Abstract:
The present invention provides a heated catalyzed fuel injector that dispenses fuel substantially exclusively during the power stroke of an internal combustion engine, wherein ignition occurs in a fast burn zone at high fuel density such that a leading surface of the fuel is completely burned within several microseconds. In operation, the fuel injector precisely meters instantly igniting fuel at a predetermined crank angle for optimal power stroke production. Specifically, the fuel is metered into the fuel injector, such that the fuel injector heats, vaporizes, compresses and mildly oxidizes the fuel, and then dispenses the fuel as a relatively low pressure gas column into a combustion chamber of the engine.

Inventors: Cheiky; Michael C. (Thousand Oaks, CA)
Assignee: Transonic Combustion, Inc. (Camarillo, CA)
Appl. No.: 11/692,105
Filed: March 27, 2007

US7,657,363; February 2, 2010
Fuel injector having algorithm controlled look-ahead timing for injector-ignition operation. (Same as US7,444,230)

Abstract:
Same as US7,444,230. Claims are different, however. Maybe a continuation. Haven't checked.

Inventors: Cheiky; Michael C. (Thousand Oaks, CA)
Assignee: Transonic Combustion, Inc. (Camarillo, CA)
Appl. No.: 12/237,302
Filed: September 24, 2008

 

[dgallup]

Recently met with Roy McAlister who holds US Patent 7628137 among many others. The rest of us can stop screwing around with half way solutions for fuel injectors. This baby will directly inject a variety of fuel selections from cryogenic mixtures of solids & liquids to high temperature gasses for various types of heat engines and fuel cells too. It's got integrated pressure sensors, IR sensors, embedded processor AND it's a spark plug.

Check with your state employment commission because when this baby hits the market we're all out of a job.

 

[SMOKEY44211]

In order to be homogenous injection needs to occur fairly early in the intake event to allow enough real time for mixing to occur. My own observations suggest heating of the fuel yeilds economy improvements. If the strategy is used in conjuction with an improvement of expansion ratio, 50% gain is not unrealistic.-------Phil

 

[franzh]

It "treats the gasoline with a catalyst that "activates" it, partially oxidizing it to enhance combustion."

Wow.

Hmm.

Wonder if it uses magnets?


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[YvesLLewelyn]

I like the basic idea but I am also a bit doubtful about the "catalyst".

 

[patprimmer]

I am more than a bit doubtful about the catalyst. Petrol plus air plus heat burns very nicely without a catalyst. Pre-burning it with a catalyst can only waste it.

Regards
Pat
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[tbuelna]

Heating gasoline or diesel fuel to it's supercritical temperature before injection will cause serious durability problems with any high pressure common rail injection system. Just imagine the issues with coking, cavitation, or even fatigue a production pump, nozzle and pintle system would have.

Conventional high pressure, common rail DI nozzles must be properly cooled just to have adequate service life while injecting fuel with temps close to ambient. At supercritical temps several hundred degrees higher, the diesel fuel would leave behind lots of deposits that would quickly degrade the super close tolerance fits and clearances within the injector nozzle.

This seems to be one of those ideas that works OK for a brief bench test in the lab under ideal conditions. But unfortunately would be impractical in a real world situation.

Regards,
Terry

 

[racecrafter]

I'm not going to hold my breath waiting for this to work....

 

[TStaples]

Here are some more current, interesting links regarding Transonic.

http://www.sae.org/mags/AEI/8078

http://www.sae.org/mags/aei/7160

-Tony Staples

http://www.tscombustion.com

 

[black2003cobra]

Thanks for posting the links, Tony! I found the second to be quite interesting.

In terms of test data, quite a claim here:
"Company engineers have doubled the fuel efficiency numbers in dynamometer tests of gas engines fitted with the company’s prototype SC fuel-injection systems, Rocke said. A modified gasoline engine installed in a 3200-lb (1451-kg) test vehicle, for example, is getting 98 mpg (41.6 km/L) when running at a steady 50 mph (80 km/h) in the lab."

I'm assuming it must be a so-called, loaded dyno wherein it can simulate full road load from not just rolling resistance, but also areo drag. I wish the article would have provided more specific information on the engine and drivetrain in the test vehicle.

Also of note:
"The new technology, in addition, is achieving significant reductions in engine-out emissions. Some test engines reportedly generate only 55-58 g/km of CO2, a figure that is less than half the fleet average value established by the European Union for 2012. Two automakers are currently evaluating Transonic test engines, with a third negotiating similar trials."

Wonder who those automakers are?

 

[patprimmer]

The data is missing because it works against their case.

Regards
Pat
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[SMOKEY44211]

There's only so many BTUs of energy available in a given quantity of fuel once the combustion process is compleated. There are some gains by increasing flame speed via pre heating the fuel thus requiring less ignition lead reducing the negative work associated with advanced ignition timing. I'm of the opinion that any thermodynamic gains are the results of increasing the expansion ratio. For reasons unknown to me the industry always publishes compression ratio. I think if you rub your chin for a minute raising compression ratio does nothing its the expansion ratio that we're trying to improve. So does the engine in question have those features in place to justify thier claim?----Phil

 

[patprimmer]

Increasing CR improves vaporisation and maybe mixing if the chamber is closer to the piston top at TDC and mostly reduces the required flame travel (depending on chamber shape), so it has it's advantages.

Also as you increase CR you also lose a tad more to the cooling system on the compression stroke due to higher charge temp, but maybe a bit less during combustion near TDC due to reduced surface area, offset by higher charge temp?

Also pressure builds quicker during the power stroke so has more time to do work.

Also presume the initial engine had 35% TE, doubling that means 70%. Seems unbelievable to me. 30% losses total between exhaust and cooling system.

If true, one additional saving could be removal of the weight cost and complexity of a cooling system, but they don't make that claim.

Regards
Pat
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