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Transonic combustion

Transonic combustion

RE: Transonic combustion

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.

RE: Transonic combustion

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

RE: Transonic combustion

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.          

RE: Transonic combustion

(OP)
Out of context, I was assuming they were referring to improvements in brake fuel conversion efficiency, (ηf,b = ηm*ηc*ηt).

Mech efficiency (ηm) would go up by eliminating the throttle and associated pumping losses, combustion efficiency (ηc) would go up from the lean-burn nature of the engine, and improvements in thermal conversion-efficiency (ηt) 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!
 

RE: Transonic combustion

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.

 

RE: Transonic combustion

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

RE: Transonic combustion

(OP)
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

 

RE: Transonic combustion

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.

RE: Transonic combustion

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

RE: Transonic combustion

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

Wow.

Hmm.

Wonder if it uses magnets?
 

eng-tips, by professional engineers for professional engineers
Please see FAQ731-376: Eng-Tips.com Forum Policies for tips on how to make the best use of Eng-Tips Fora.
 

RE: Transonic combustion

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

RE: Transonic combustion

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

RE: Transonic combustion

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

 

RE: Transonic combustion

(OP)
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?
 

RE: Transonic combustion

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

RE: Transonic combustion

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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RE: Transonic combustion

Just some general comments.

The primary benefit of CR it that it increases peak combustion temperature. Thus, the theoretical thermal efficiency is improved (see Carnot again). This is realized as improved useful work under the P-V diagram for the same amount of fuel.

It takes a large combustion temperature increase to move your thermal efficiency. For example, if your peak combustion temperature is 1500 F and exhaust is 800 F, your best possible efficiency is 36%. If you go up to 1800 F and keep exhaust at 800 F your best possible efficiency is 44%. To take it up to 70% would require 3730 F at the same exhaust temperature.

Cooling burden for increased CR should net lower, as more of the fuel energy went to work rather than heat. However, more of the heat goes into the block rather than out the exhaust because of higher heat transfer during combustion, so I'm not sure that would hold at all possible conditions. You lose more to friction due to higher cylinder pressures, but I don't know how significant that is.

Given the very low beneficial pressure remaining at the tail of the combustion, expansion ratio is a small fish (but non-zero). Look at a P-V diagram of a combustion event and think about how much beneficial area you could capture by delaying exhaust timing a bit - it's not going to be that much. Remember that a lot of those are logarithmic, so watch your scales or your eyes may lie to you.

RE: Transonic combustion

JSteve2 - I think what you wrote is not quite right.  
Higher CR may increase peak combustion temperature but this increase is from extra work done in compression - if the same amount of air and fuel is burnt the the increase in efficiency is due to the expansion ratio being greater (as other people have said).
 The basic equation for thermal efficiency is - "one minus one over R to the point four". The "R" is the CR but it actually refers to the expansion ratio - the equation assumes that the compression and expansion ratios are the same. The actual compression ratio does not come into the equation.
 On a P-V diagram the remaining temperature and pressure  when the exhaust valve opens may appear to be very little - but remember that petrol engine exhaust manifolds are still hot enough to glow red - there is plenty of energy left when the exhaust valve opens. By raising the CR from 9:1 to 18:1 (for example), the extra expansion is enough to raise the TE by 10% or so - but there is little energy to be recovered after this point by further raising the CR/ER.  
   Speaking of glowing manifolds - I don't think a normally aspirated diesel manifold would ever get hot enough to glow - I've certainly never seen one glow.
A big part of the diesel's overall fuel efficiency is the reduction in intake pumping losses - possibly even slightly more that which comes from the increased ER.  

RE: Transonic combustion

Black2003Cobra,

Due to our agreements with our partners, we are not disclosing the OEM's with which we are working.  For obvious IP implications, employees are not allowed to share sensitive technical information.  However, I will post links regarding public information as they come along.  I can say that your dyno assumptions are correct.

I can only apologize to the engineering community for the marketing hyperbole.  It's marketing's job to promote what we are doing, to a wide audience range.  It's difficult to do that job without using descriptors like "revolutionary." YvesLLewelyn's comments reminded me that the reason that Engineers are not allowed to do marketing is that we are too literal.  If an engineer were in charge at McDonalds, they would go bankrupt.  No one would want to buy hot, dead cow.

JSteve2 is correct.  Carnot tells us there is a lot of low hanging fruit in terms of IC engine efficiency. Because so little useful work is extracted from the fuel in terms of percentages, at low loads (like highway cruise,) it doesn't take a huge increase in overall efficiency to dramatically raise the fuel economy.  Our website has a good explanation at:

http://www.tscombustion.com/autoinefficiency.html

I do have to take exception to Pat's broad brush statement that "pre-burning" fuel in a catalyst can only waste it.  (I have a lot of respect for Pat, BTW, based on the depth of his contributions to Eng-Tips!)  Theoretically speaking, lets assume you consume a small percentage of the energy content of the fuel in the catalyst, which then allows you to increase efficiency, via an otherwise unavailable mechanism, during combustion. If this mechanism saves more fuel than is consumed by the catalyst, at a given power level, then it results in a net gain.  I wouldn't define that as a waste, when you look at the system as a whole.   

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

Yves-
Carnot cares nothing about compression/expansion ratios. The "R" is the temperature. You need to know the temperature you are taking work from and the temperature of your heat sink to know the theoretical thermal efficiency. The fact that some of the temperature is from compression work is not relevant (but certainly not all of it - there are many reasons your peak combustion temperature goes up which go further than just the temperature increase by compression, see PatPrimmer's post for some of them).

Higher combustion temperature really is the driving force behind better efficiency with higher CRs. We could go crazy on this, but alas NOx emissions have come into play and we are trapped with 48-ish % thermal efficiency. I will call BS on any system claiming better than 48% thermal efficiency until I see the data and a good explanation.

Yes, there are a few percentage points to wring out at the end, but not very many, and it complicates other operations in the engine to try to get all of it. 10% is too big, but I won't hazard my own SWAG as it would likely be just as far off. I can tell you that if is was as high as 3%, someone would be doing it in certain applications already.

RE: Transonic combustion

(OP)
Tony - Thanks again for stopping in.  I appreciated the humor, by the way.  The second SAE article you provided a link to earlier mentions CR in the range of 16-20, and 13 for gasoline engines.  So was your test engine a CI or SI motor?  Can you tell us what the brake fuel-conversion efficiency of the test motor is/was?  Any other data you could provide would be appreciated.

Eric

RE: Transonic combustion

Steve - the "R" I referred to in the equation "1 minus 1 over etc." is actually the compression/expansion ratio.
I realize I have confused matters slightly by using a capital "R" (which is normally the symbol for the Rankine temperature scale) - I should have used a small "r" - (starting to sound like a pirates' convention).  
The quoted equation - "1 minus 1 over etc." is actually a different way of expressing the equation for thermal efficiency of "T1 (highest temperature) minus T2 (exhaust temperature) all over T1".  T2 is the temperature that T1 is reduced to after adiabatic expansion by an "r" amount. I don't see that the amount of compression comes into the matter at all.
 As for "applications" - the whole idea of the Atkinson Cycle is to wring a little more energy out of the tail of the P-V diagram - and the diesel as well is the same.
 I would think that the TE of a 9:1 CR/18:1 ER Atkinson Cycle petrol engine operating at WOT/maximum torque RPM would have a very similar TE (if not a little better) to the TE of a comparable diesel - that is; something approaching 10% better than a normal 9:1 petrol engine.            

RE: Transonic combustion

Yves - I didn't look at the equation you were referring to, I just had thought you were indicating that the compression ratio was part of the Carnot equation. Atkinson certainly offers some assistance, I believe the Prius has a 38% TE. That's at least partially due to the fact that they can often run at a steady state point as well. However, since diesels regularly run 44% TE without Atkinson I think it's still clear that compression ratio is the bigger fish. I'm not saying there is no value in Atkinson in some circumstances, obviously the Prius gets some use out of it, but the numbers from the OP are not within my experience, and if they achieve them it's not primarily due to expansion ratio.

RE: Transonic combustion

I would have thought the method was proprietor, but the results would be shouted from the foof tops IF THEY WERE GOOD.

Everywhere I worked in technical marketing roles, a press release or technical data might go along the lines of:-

By improving the X process by Y we achieved an improvement in Z of Q% by test method M. The conditions were controlled by N

Further independent tests were carried out by the NATA registered laboratory B and their report can be supplied if you are interested. We can supply samples so you can conduct your own tests. Please contact us via XXXX for further action.

The proprietary details are of course not included. Hypothetically it might be something like we improve combustion efficiency and pressure build rate by controlling a:f mixture quality in a stratified zone within the chamber so that the nano  particle size and localised control of a:f aids rapid but controled combustion.

Missing is the details of how you achieve and control the stratified charge and the fuel particle size.

I am starting to smell reptile oil here. The question is if it is very old or very new. My tip it is from a current living reptile like snake.

Regards
Pat
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RE: Transonic combustion

For our dog Kennel, we tried to apply the Carnot Heat Cycle principles, but never with any success.

Mike McCann
MMC Engineering
Motto:  KISS
Motivation:  Don't ask

RE: Transonic combustion

Pat,

It's good for you to be skeptical.  That is as it should be in Engineering. Fortunately, our OEM partners aren't consulting with you regarding your olfactory opinions! winky smile

As I've stated previously, I cannot share technical details that are not yet public due to legal obligations.  It certainly isn't from a lack of personal desire.  If I could, I WOULD be shouting from the rooftops.  It has to do with the current stage of our company.  IP protection is a very critical aspect of what we are doing, to protect the interest of our investors, stakeholders, and OEM partners.

I jumped in here merely to share the public information that I didn't see posted, per black2003cobra's original request. The kind of information you refer to is being shared with our OEM partners, after ensuring our IP is protected.  This is not atypical in this type of situation.  

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

Steve - In this Wiki article is an interesting list of various engines' TEs.
http://en.wikipedia.org/wiki/Brake_specific_fuel_consumption
The Prius Atkinson 13:1 ER engine is listed at 37% - other Otto engines are given as 27%. Both these figures would be with the engine running at its most efficient - so presumably the 13:1 Atkinson effect is worth about 10%. Note that 37% is a bit higher than the automotive diesels in the list which are up to 36%.
Presumably a Prius engine with an expansion ratio of 18:1 would have a TE of 40% or so - matching the TE of a normally aspirated 18:1 diesel - this is my argument - the TE is all in the ER.
Just how the Volvo truck engine listed makes nearly 45% is a bit of a mystery.
I have been interested for a long time in the reasons diesels have such a high TE - a lot of "high-powered" text books give the same reason as you - high CR and high combustion temperature - but I still think the major factor is the high ER - the high CR being a necessary evil.
 I am quite happy to believe that there may be a valid thermodynamic reason why a diesel may have a slightly higher TE than an Atkinson engine of the same ER - but I don't know what it would be.

 
 Atkinson engine of the same CR/ER     

RE: Transonic combustion

Yves,
You may notice that everything on that chart over 39% is direct injected, which enables high compression ratios. That Volvo truck engine is right in the mix for a modern on-highway truck - there are not many listed on that table but they are all in there (42-44 likely). If there were no other factors, that Prius Atkinson is worth about 37% (10/27), not merely 10%. However, there are a number of other factors, so it's difficult to say how much of that is attributable to the Atkinson portion alone.

For a heat engine, you only have two ways to improve the theoretical efficiency: increase the high temperature or decrease the low temperature. Extended expansion goes after the low end, and high compression goes after the high end. There is a limit to both - ambient air temperature at the bottom and your NOx generation limit at the top (unless you can ignore that - see the marine diesels at the bottom of that chart). Also, high ER in the absence of high CR yields a very low power density. The Prius survives that because it is a hybrid (98 hp out of 1.8 L).

Of course, there are any number of ways to go after actually achieving your theoretical efficiency once you establish it, but you can never go over it.

We could just be having a debate on terms. A high ER by it's nature indicates a high difference between the combustion temperature and the exhaust temperature - think about the cylinder conditions after the combustion chamber has expanded 18:1. Whether you achieve a high ER by starting with a high CR or by delaying exhaust opening, it may not matter too much how one thinks about it.

There may be more to a profound ER than my instincts were telling me initially. It will be interesting if someone develops a commercial high ER product that explores the limits of that.

RE: Transonic combustion

I'm just looking forward to seeing the demonstrator vehicle when it hits the streets.  Can one of you TS employees be sure to start a new thread when the vehicle is available.

- Steve

RE: Transonic combustion

On studying the data and papers as presented, I find the figures hard to justify as there are no fixed points of reference. 50% better than what. A T model Ford ?

Also while some of the techniques mentioned are not exactly new, there is reason to expect they may improve fuel economy if other traditional problems are solved, however the magnitude claimed is frankly unbelievable.

As you are a consultant I can appreciate that you should be ultra conservative about releasing anything about a customers project.

One of the papers I had not previously read does give the mechanisms but not the details with regard to rapid combustion and stratified charge and fuel regulated rather than throttle regulated diesel like features.

Regards
Pat
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RE: Transonic combustion

(OP)
Well not really knowing what cycle to use, just for the heck of it, I ran a quick thermodynamic simulation for two cases just for the standard Otto cycle.  I just used "ideal" (non-realistic) valve timing.

For the first case, I used rc = 9.5, a burn duration of 50 degrees, spark at MBTT, and an equiv ratio = 1.

Then for the second case, I used rc = 20, a burn duration of 20 degrees, spark at MBTT, but backed off on the equiv ratio until indicated work from both motors were the same.

I found that therm-conv efficiency went up by about 22%, and comb efficiency by about 2.5%.  The combustion efficiency was taken from a fit to a data plot, and it's a little shaky, at best.  I recall other plots in Heywood for fuel-conv eff vs equiv ratio, and I should take a look at that.  It would be more accurate.  Be that as it may, from just a crude estimate here, the model results are suggesting around 25% improvement.  Most from just the higher rc.

Because I used less fuel to get the same gross work, peak temps weren't much different.  Peak pressure was significantly higher for the high-rc/short-burn case, however.  The heat transfer was definitely higher around peak pressure for the high-rc/short-burn case, but then dropped below that of the lower-rc/long-burn case throughout most of the expansion stroke.  Overall, there was less heat transfer through the cylinder walls and out the exhaust for the high-rc/short-burn case.

(The model uses Woschni's hc for convective heat-xfer and a black-body approximation for radiative heat losses.  The later, being fairly small by comparison.  Burn is via Wiebe burn fraction.  It does not include frictional losses, nor did I include pmep losses.)

So some additional improvement should certainly be possible by eliminating pumping losses from the throttle.  Not sure how much that might improve overall mech efficiency, but someone might take a wag at it.  I am not confident it would get the overall fuel-conv efficiency up enough to show a 50% improvement.  But again...maybe someone has some numbers to throw at that.

I am a bit confused by what the reported gain in fuel-conv efficiency really is.  The SAE 7160 article (link given by Tony above) says it doubled.  This other article (link below) says a 50% increase.  It says,

"That's where a new system from Transonic Combustion comes in. The California-based startup has developed a fuel-injection system that can improve the efficiency of gasoline engines by 50%."

Here is the link => http://www.inhabitat.com/2010/03/09/transonic-combustions-super-efficient-gas-engine-gets-98-mpg/

The other peswiki.com link in Tony's post above suggests 50-75%.  It would be good to know what the true baseline is.

Thanks for the other links, Tony.

Regards,
Eric

RE: Transonic combustion

(OP)
Just noticed in the peswiki.com link that it mentions a modified gasoline engine was used.  I interpret that to mean an SI engine.  But no spark for transonic setup, I assume.  Mentions a doubling of ηf,b.

"Test Results
Company engineers have doubled the fuel efficiency numbers in dynamometer tests of gas engines fitted with the company's prototype SC fuel-injection systems. A modified gasoline engine installed in a 3200-lb (1451-kg) test vehicle, for example, is getting the equivalent of 98 mpg (41.6 km/L) when running at a steady 50 mph (80 km/h) in the lab. The new technology 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."

RE: Transonic combustion

black2003cobra,

I didn't notice that error in the peswiki article.  It was a modified compression ignition engine. That was an error by the author.  That has been published correctly in other articles. Good catch.  I try to only post articles that are reasonably accurate. (We recently got written up by our local newspaper, and the article was flattering, but so full of technical errors, that I see no sense in sharing.  Non-technical people have a hard time writing about technical things.)

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

(OP)
Looks like the SAE 7160 article is wrong, too.  (Looks like a direct copy to me.)  Thanks for the clarification, Tony.

Eric

RE: Transonic combustion

I think the "50% better" needs to be clarified.
50% better than a SI engine's TE of about 30% - this can mean 30% plus 50% of 30% to give a TE of 45% (30 plus 15) or 30% plus 50% to give 80%.
 45% I could maybe believe (this is in diesel territory) - but not 80%.
 98mpg in a 3200lb car at 50mph - on a small US gallon? This is about 118mpg on a "proper" Imperial gallon. This does not seem very likely.  

RE: Transonic combustion

(OP)
I was assuming the improvements they mentioned were relative, not absolute.  For example, 50% better than an efficiency of 30%, being 45%.  If I put my consumer hat on, and say I was getting 45 mpg vs 30 mpg, I would say that was a 50% improvement.  So I would translate that to a 50% (relative) improvement in ηf,b.  That's how I'd look at it anyway.

RE: Transonic combustion

Engineers assume that a relative improvement to an unspecified baseline is absolute flackery.

 

Mike Halloran
Pembroke Pines, FL, USA

RE: Transonic combustion

blackcob - 45% seems like a perfectly reasonable claim and is about what you would expect from their system. In its higher CR forms (they mention 16 to 20:1 somewhere) it would appear to be little different in concept or performance to a conventional diesel engine.
None of this explains the 118mpg claim.

RE: Transonic combustion

black2003cobra,

Relative improvement is the correct assumption.  As Engineers,  we love to talk geek.  The ROW however doesn't understand ηf,b, for example. So, our marketing folks have spelled things out in something they do (well, sometimes anyway) understand, m.p.g.

MikeHalloran,

Per my earlier comment, that's why they don't let Engineers do Marketing.  But, I agree with you totally. I will talk with our Marketing folks and see if they will define that more concisely in future releases.

Yves,

Just curious. What 118 mpg claim?   

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

Tony - for a 3200lb car at a steady 50mph you have been claiming 41.6km per litre?
Converted miles per US gallon (3.79l) this is 98mpg - converted to miles per Imperial gallon (4.55l) this is 118mpg. Mileage in Imperial gallons makes more sense to people in Oz,UK,NZ.     

RE: Transonic combustion

black2003cobra,

I have an engineer friend who was employed by Transonic.  You may already know him, as he is a Ford performance enthusiast and ran his own business for a while selling supercharger kits for (I think) the 4.6 liter engine.

In any case, let me know if you want to pursue an off-line discussion on Transonic, and perhaps I can facilitate getting you and he together on the phone.

I assure you that he is a very ethical guy, and will not reveal to you any Transonic company sensitive info.

Dick  

RE: Transonic combustion

Yves,
 
Now I understand where you got the 118 figure. I'm proudly guilty of being a unitationaly myopic American. I didn't see a specific conversion reference in the thread. I've seen some really good data, but not 118 mpg(US).  Please understand that it's not a claim of 98 mpg on the Federal EPA cycle.  It's simply a steady state fuel economy figure that has been reported from chassis dyno testing, with the appropriate 50 mph aero drag, and mass, etc . . . factored into the dyno load.  In a nutshell, Transonic is claiming this is approx. 50% better than a typical Diesel CI pass. car of similar displacement, power, etc . . ., and closer to 100% better than the equivalent SI gasoline engine under the same conditions. This is public information, but perhaps not been made concisely enough (my opinion.)

Transonic is using those numbers because that particular test plays right to the sweet spot for the TSCi technology - light load/cruise.  Those operating conditions demonstrate the biggest relative improvements of TSCi. Since this just happens to be where most typical pass. car engines spend 95%+ of their operational time, I think this is a very big leap forward.  

I don't want to overstep my professional bounds here, but because of my involvement, I take it personally when I see statements like "snake oil", and "flackery".  However, until we have finished putting together a more comprehensive, independently verified (outside test lab), data package, and reach the appropriate time when our team decides it's best to release such data, I'm thick-skinned enough to keep biting my lip.  I'm personally very proud of the work that Transonic's people have done to take an initial good idea from our founder, and realize it, improve it, and develop it to where it is today.

I appreciate that everyone is interested, but all of the technical analysis being discussed here is based on the limited amount of marketing information that's been released.  It is what it is; marketing information. It's designed to raise interest in what we are doing, and to attract potential customers, who get much more in-depth data after signing an NDA.

In my opinion, Transonic isn't asking anything from the general public, so we don't have an obligation to publicly reveal anything unnecessarily.  Doing so at this stage carries the risk of showing a potential competitor too much.  I completely understand the skepticism, because the numbers are big, and you don't have all the details. I know I would be myself.  Wait until more in-depth data is ultimately released for public consumption and scrutiny.  I cannot give specifics, but I will say it's in the plan.  That's only logical, as we move forward as a company.  When more information is released, I will be sure to post a link to it here. That is what the OP requested.


 
 

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

Dick,
 
Not necessary.  I know to whom you are referring very well. I still have his number.  He, like me, was one of the earliest hires at TSC.  He was a tremendous contributor to our company, and I wish he hadn't departed as early as he did. He still hangs out with "the guys" fairly regularly.  When you have as many car crazy horsepower junkies on staff as we do ... .

It's actually funny how many 400+ horsepower cars sit in the parking lot of our Green-Tech company.  I'm personally responsible for a couple.  I guess it like hiring a computer hacker to be head of cyber-security.  Advancing the state of the art in combustion is penance for my personal consumption of gi-normous (highly technical term that) quantities of Shell Ultimate with "Nitrogen."  Now, if I could only get them to sell me Shell Ultimate with "Nitro"! thumbsup

 

-Tony Staples
www.tscombustion.com

RE: Transonic combustion

Tony

I Was extremely sceptical, then I went back and read your history and pulled my head in somewhat. I am still sceptical as I am a scientist, and the data to date lacks scientific method, but I do genuinely hope I am proved wrong.

Regards
Pat
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RE: Transonic combustion

Tony - You have said it in plain English - you are claiming 50% better than than the equivalent diesel mileage and about 100% better than than the equivalent SI mileage (does this equate to a TE of about 60%?).
 You words and attitude seem sincere - so like PP (I think) I will reserve judgement until further evidence.
 If true it would be an amazing achievement.   

RE: Transonic combustion

It would indeed be an amazing achievement if these claims are substantiated.  Power, torque & BSFC curves from the engine would be interesting.

- Steve

RE: Transonic combustion

seems too good for the motorists to have !!!
I cant see the gov,or the petrol companys  actually going along with it just yet, maybe 12 15 years,
just think of all the lost revenue the will loose,

would be good to actually have some on the road, to put the sceptics at rest !!!

regards  marcus

One does nae have to know how some thing works, to know that it is nae working right

http://s545.photobucket.com/albums/hh369/marcusaurailius/

 

RE: Transonic combustion

patprimmer,
I concure and thank you  I now know that I have to publish BSFC figures. her is a link to a recent article
http://www.just-auto.com/article.aspx?id=93295



"I would have thought the method was proprietor, but the results would be shouted from the foof tops IF THEY WERE GOOD.Everywhere I worked in technical marketing roles, a press release or technical data might go along the lines of:-By improving the X process by Y we achieved an improvement in Z of Q% by test method M. The conditions were controlled by NFurther independent tests were carried out by the NATA registered laboratory B and their report can be supplied if you are interested. We can supply samples so you can conduct your own tests. Please contact us via XXXX for further action. The proprietary details are of course not included. Hypothetically it might be something like we improve combustion efficiency and pressure build rate by controlling a:f mixture quality in a stratified zone within the chamber so that the nano  particle size and localised control of a:f aids rapid but controled combustion.Missing is the details of how you achieve and control the stratified charge and the fuel particle size."

cheers Malbeare

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