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DI Engines

DI Engines

DI Engines

(OP)
hi!!

will DI engines ever be used in the US?  NOx is a catalyst problem. but are there any developments in the field of catalysts that will solve the probelm?

HC's and particulates are related to in-cylinder phenomena such as wall wetting, pool fires and insufficient time for oxidation of particulates etc. there is lot of reserach going on to identify methods to eliminate these causes. but how long will the auto industry fund DI research projects? is it true that ford and GM are trying to cut spending in DI research? have they given up on DI research?

cadillac claims to have a v-12, 750 hp DI with more torque, fuel economy and low emissions. but they havent said how they achieved all three. its for their new concept car which they claim is inspired by the F-22 fighter aircraft.
it also has cylinder de-activation.

RE: DI Engines

There was a press release a couple of days back by the Orbital Engine Company and Johnson Mathey, announcing some new super-duper DI supercharged 2 stroke / good cat combination that easily exceeded Euro 4.

Having driven one Orbital's cars I can assure you that the claims for torque and fuel economy are true, and the emissions I'll believe.

"PERTH, Australia, Nov. 11 /PRNewswire/ -- Orbital (NYSE: OE - news) and Johnson Matthey today announced that as a result of a joint development effort Orbital's direct injection system combined with Johnson Matthey's advanced catalyst technology has achieved a major technical breakthrough that will reduce both the cost and risk of applying direct fuel injection to automotive applications.

A test vehicle featuring the Orbital Combustion Process (OCP) direct injection system achieved a 12% fuel economy improvement (over the PFI baseline vehicle) and Euro 4 emissions standards with a specially developed Johnson Matthey 3-way catalyst. The test results were achieved in a standard 4-door sedan powered by a 2.0 litre, 16-valve, 4-stroke engine running the latest iteration of the OCP direct injection system.

The emissions control system, developed in conjunction with Johnson Matthey, incorporates advanced 3-way catalyst technology, which is not reliant on ultra low sulphur fuel to meet these tight limits. To verify the durability of the system, the catalyst was severely hydrothermally aged by Johnson Matthey at temperatures up to 1050 degrees C.

Director of Orbital's Automotive group Dr. Rod Houston described the latest test results as a significant step forward in proving the suitability of OCP technology for global applications in the near term.

``Alternative direct injection systems have been reliant on lean NOx trap systems, to achieve their emissions targets. The durability of these systems in real world driving conditions has not been fully proven, especially in the United States where the sulphur content in the fuel mitigates against their use.''

``A key characteristic of Orbital's lean-burn combustion system is the very low raw emissions of hydrocarbons (HC) and oxides of nitrogen (NOx) under stratified conditions. In addition, Orbital has developed new intellectual property to optimise the interaction of the combustion system and the after-treatment system. These test results demonstrate that OCP direct injection could be applicable in regions such as the United States, where the sulphur content of the fuel prohibits the use of NOx trap systems.''

Dr. Martyn Twigg, European Technical Director of Johnson Matthey stated: ``This is an excellent result which allows fuel economy to be gained without the need for the ultra low sulphur fuel necessary with NOx trap systems. Vehicles equipped with NOx traps and running on appropriate low sulphur fuel demonstrate significant improvements in fuel economy. This result demonstrates a good interim strategy to lower CO2 emissions through improved fuel economy until low sulphur fuel is widely available.''

The new test results are the latest of several major developments involving the commercial application of Orbital technology, including:


    *  General Motors unveiling a global V8 concept engine incorporating
        OCP air-assisted direct injection at the Frankfurt Motor Show in
        September

    *  Delphi Automotive Systems and Orbital signing a technical transfer and
        license agreement giving Delphi rights to manufacture and sell
        OCP technology in August


Orbital is a leading international developer of engine technologies using direct in-cylinder fuel injection and lean-burn systems for enhanced fuel economy and lower emissions. The company serves the worldwide automotive, marine, and recreational and motorcycle markets. Headquartered in Perth, Western Australia, Orbital stock is traded on the Australian Stock Exchange (OEC), the New York Stock Exchange (OE) as well as the Berlin (ORE) and Frankfurt (OREA) Exchanges."

End of release

Cheers

Greg Locock

RE: DI Engines

I am personally aware of some advanced research into DI using gaseous fuels.  Almost all of the problems described such as wall wetting, pool fires and insufficient time for oxidation of particulates are eliminated.  Lower injection pressures are also possible since the fuel does NOT have to be vaporized when injected.

Stay tuned, will keep the thread posted when more info can be released.

Gregs Orbital experience is also duplicated by an associate of mine in Oz-Land, but almost a decade ago.  Wish it could make here to the States!

RE: DI Engines

Hi not been on here for a very long time!!!

Now then, DI...

There will indeed be DI engines used in the US in the not so distant future. It is, however, very unlikely to run stratified at anything other than idle. This is becasue CARB regs. prohibit the reduction of one emission gas CO & HC in this case at the expensive of another, NOx. Ok the lean Nox traps that can be used elsewhere are quite effective but rules are rules!!!

The benefits in fuel economy that Homogenous charge (and split injection for that matter) DI engines bring does mean that DI technology will be used. In fact the increase in thermal efficiency etc ensure that PFI engines will start to look quite outdated!!!

Anyway I hope that DI work continues or I will be looking for another job!!!

MS

RE: DI Engines

Not sure of the comment about more torque.  DI fuel economy comes from running stratified and the thermal benefits.  At WOT, even DI engines run stoic., or else you lose power.  With DI, you even lose the benefits of cooling the intake air with MPFI and would get less air in the cylinder each cycle.  less air + stoic air/fuel = less torque.

The only significant benefit with DI is fuel economy gains for low loads, and the lower the better.  The issues as I see it are NOx emissions,  durability of the fuel system, and increased cost.  

RE: DI Engines

Sure,  But the Orbital engines are usually 2 strokes, so for a given engine size (ALL other things being equal) the torque is doubled, for a given speed.

Cheers

Greg Locock

RE: DI Engines

This may answer some GDI questions:

Who makes 2S and 4S GDI Systems
FAQ71-169

Orbital Engine company has many 2S air assised direct injection system in production vehicles today. Customers include Mercury Marine, Bombardier, Tohatsu, Aprilia and many others.

In the past few years OE has been working with 10 major automotive companies and has several concept engines being shown at auto shows now. OE has presented papers at SAE and other venues all over the world and is very active in design and testing of both 2S and 4S engines. Their engines meet or exceed emissions regs. thruout the world and typical fuel economy savings are 50% for 2S engines and 20% for 4S engines.

A group of us(has also formed a club(137) at:http://clubs.yahoo.com/clubs/oec

Check out Orbital Engines wesite at:http://www.orbeng.com.au/orbital/whatsNew/whatsNew.htm

If there is interest here please feel free to ask questions.

Have a nice day, Tom  

RE: DI Engines

The DI engines are already in the US. Aprilia motorcycles licensed the DiTech technology from Orbital. You can buy an Aprilia 50cc DiTech scooter right now for under $2800. It uses DI technology, burns very little oil for a 2-stroke, goes 60mph and gets 125+mpg.

These little scooters rock...

check them out on www.apriliausa.com

RE: DI Engines

FireLover,

More torque is possible when running DI. This is down to 2 things: -

In the first instance the raised compression ratio and cooling of the chamber from the injection of the fuel.

The maximum gain is in the use of 'split injection'. Whereby part of the fuel is injected at the beginning of the intake stroke (thus cooling the charge) and the 2nd part is injected at the top of the compression stroke. The outcome of this is that more torque can be produced (as opposed to a similar PFI engine)

Well in theory at least (or I am out of a job)


MS

RE: DI Engines

It surprises me that diesel engines inject fuel directly into the combustion chamber but this seems to have never been the case with production gasoline engines.

What is the reason for that?  I saw on Bosch's website a claim of 15 to 20% gasoline fuel economy improvement for this one technique alone, making it strange why this has never been done before.

My apologies to you guys in the auto world.  I've spent most of my career in other areas and recently became involved in cutting edge electronic fuel injectors.

RE: DI Engines

charlie, I'm not sure how to answer your post until you have done some basic homework. New CIDI and SIDI are complicated engines. Bosch, Mitsu. and Siemens websites and some other Gasoline HPDI manufacturer's websited are full of bull. All current 4S Gasoline HPDI systems are total failures and have been discontinued from production.

Most auto manufacturers are now concentrating on low pressure air assisted direct injection( Orbital's OCP).

The HPDI manufacturers are still trying to get their system to work and maybe they will. The fact is that OCP works now, even with High S gas.

Tom

RE: DI Engines

charliebPE asked about direct injection gasoline engines in production.  Actually the first production automobile with fuel injection was the 1955 Mercedez-Benz 300SL (I think I have the model right) which injected the fuel directly into the cylinder.  This direct gasoline injection design was abandonded by Mercedez because they couldn't build injectors that would last in that enviornment.  So GDI isn't a new idea, it is just that the changing requirements of the automotive engine, and the more sophisticated materials, are now beginning to make it a viable alternative.
A similar evolution occurred with electronic fuel injection, which was in production as early as 1957 (Nash?)!  It wasn't unitl emission controls and CAFE standards became too stringent for carburetors that its use was widespread.

RE: DI Engines

Thanks for your info Tom.  I checked out Orbital's extensive website, but could not read all of it.  Looks like they have some interesting technology and I hope it gets over here.

But it surprises me that 3 companies; Bosch, Mitsubishi, and Siemens; all make the same mistake and fail miserably at GDI.  These guys aren't exactly industrial lightweights, which leads me to believe there is some inherent physical problem that they are banging their heads on.  Am I correct?  If so, what's the big problem?

I'm curious.

Charlie

RE: DI Engines

Hi Charlie

You are right, Bosch, Mitsubishi, and Siemens; all all have made the same or similar mistakes and failed miserably at HP GDI.  These guys aren't exactly industrial lightweights, which leads me to believe there is some inherent physical problem that they are banging their heads on. They have spent zillions of $ on HPDI, actually put a million or so engines in production vehicles, which cost them zillions more and significant embarasement.

Our understanding of the main problems that they have failed to overcome are as follows:

1) HPDI( high pressure single fluid direct injection) relies on injection of the gasoline at 75- 150 bar. Generally they direct this HP jet at a curved bowl in the top of the piston and rely on the bounce back of some of the fuel to the spark plug for ignition. This process causes wetting of the piston, cylinder walls, injector, plug etc. They have and still are trying to use swirl and tuble devices to get a better and more uniform mixing of the fuel and air. Also most of these systems can only get the fuel particle size down to about 20-40 microns, which is too big for efficient and low emissions combustion.

2) as a result of items mentioned above, several problems happen. a) fouling in the cylinder of the injector, plug and elsewhere, b) this combustion causes excess NOX and other emissions which poison even the very expensive and special cats. they use.

3) In an attempt to overcome 2) above, they have insisted that owners use only ultra low sulfer gas. This creates other problems, as when you reduce the sulfer content, you reduce the lubricity of the fuel and this causes all sorts of other problems, like the High pressure fuel pumps wearing out and all other moving parts in contact with the fuel.(there are long stories behind all this stuff).

4) In an attempt to overcome 3) above they have(we hear), some manufacturers in Europe have now restricted the owners to use of only one type fuel. This is a special high octane, ultra low sulfer gasoline, which has a special lubricant additive. It is Shell "Optimax". We hear that this is causing more problems because the lube additives cause other fouling and cat poisoning problems.

To my knowledge, because of all the problems listed above, there are no production engines being sold to the public at present. The companies involved have literally hunders of engineers working to solve these problems.

I am not trying to over simplify this, but Orbital Engines OCP Low pressure air assisted direct injection system does not have any of these problems.

We hear that the affected companies are testing OCP now while trying to fix their own HPDI systems.

Time is running out on these turkeys as new emissions regs are coming into effect. Hope that helps some.

Have a nice day, Tom

 

RE: DI Engines

The essence of the problem here is incomplete combustion .Incomplete mixing of air and fuel ,unevenly distributed fuel or   mixture across the combustion chamber and
 uneven temperature distribution across the flame front.
Catalizers are not ideal as they are basically garbage  pails used after the engine has been allowed to do a very messy job of combusting .....
I feel the industry is going in the wrong direction by trying to mix a liquid (fuel ) with a vapor  (air).
Two vapors  mix much better and are more uniform in distribution of their respective molecules of gasses.
Fuel must not be injected under low or high pressures but VAPORIZED then MIXED with another GAS .
So instead of having carburators , we should have had fuel VAPORIZERS ....
The particulates ,NOx and other dirty little molecular friends are happy to reproduce at temperatures which are not ideal for combustion.A flame front varies in temperature because the head ,valves ,the cylinder walls and the pistons are all working at different temperatures.
Cylinders made of steel absorb heat at a different rate than the aluminum pistons , the stainless steel valves and the aluminum heads .
SO...how to reduce flame front varriations of temp.?
One good way is to reduce the heat transfer to the head , to pistons and valves and to the cylinder walls.
A very significant reduction can be acheived with a thermal barrier =a ceramic coating deposited on the piston top,valve faces and combustion chambers. The cylinders cannot be treated with the same ceramic because the rings have to have the right material to seal properly.
The diesel truck industry has researched this since 1988 and  the results are in the public domain.
A fantastic engine which was tested by Ford in its GTP race car around 1992 was adressing these weight and heat transfer or heat losses problems.It was all plastic and it was the  brainchild of Matthiew Holtsburg of New Jersey.This was a shot straight to the problem.

RE: DI Engines

Riktoo, wouldn't using gaseous fuel dramatically reduce the power output of the engine, by reducing the amount of air that could be injested each cycle?  Correct me if I'm wrong here, but doesn't gasoline vapor occupy about 160 times as much space as an equivalent mass of liquid gasoline (at 1 atm, 68 degF)?

RE: DI Engines

Charlie, here is an article which tells part of the story and only part of the truth. The fact is that Mitsubishi lost zillions on their HPDI systems. Exceprts :

Automotive News, Oct 15, 2001

Mitsubishi moves to stem sales drop; Automaker projects 3% downturn in U.S. (Brief Article) James B. Treece.
Full Text: COPYRIGHT 2001 Crain Communications, Inc.

TOKYO - Mitsubishi Motors Corp. expects to limit the drop in its U.S. sales this year because of fallout from the war on terrorism to as little as 3 percent, COO Rolf Eckrodt said last week.

Speaking at the launch of the eK-Wagon minivehicle, a new model for Mitsubishi, Eckrodt said consumer nervousness in the wake of U.S. attacks on Afghanistan could reduce the company's U.S. sales this year by 6 percent from an original forecast of around 320,000 units.

"In other news, Eckrodt said Mitsubishi will not push its gasoline direct injection engine throughout its product lineup after all.

Gasoline direct injection ``will be further developed,'' Eckrodt said, especially in ways that combine it with other technologies that improve fuel economy or reduce emissions.

But will Mitsubishi use it in all pricing categories and all cars? ``I don't think so,'' he said. ``It depends on the car.''

After Mitsubishi commercialized its gasoline direct injection technology in the mid-1990s, it went on a campaign to promote its engines as differentiators in the market.

In 1997, Mitsubishi said all its cars would be powered by gasoline direct injection engines, with the possible exception of its minicars, which, by Japanese law, have engines smaller than 660cc.

But the technology has an Achilles' heel. It cannot use gasoline that has more than a tiny amount of sulfur. That has ruled out its use in California, for example."

RE: DI Engines

OK Ivymike good thinking ,you are absolutely right, but let me throw another question at you.
Of course fuel in the liquid state occupies 160 times less volume than in the vapour state.But a few drops of fuel occupy very litte space in the intake or chamber. Actually, fuel vapours would compete with air molecules for intake space .The energy extracted out of present liquid fuel/air is only about 25 % of the total energy potential. So this type of mixture wastes 75 % of the available energy.Liquid gasoline does not burn until it changes to the vapour state. Now if we can  supply a mixture of two vapours that burns more efficiently and produces less byproducts , we can assume that we do not have to inject as much volume.By not having to inject so much mixture volume could the fuel vapours produce equivalent power ?  
Now think about this , atmospheric air is made up of about  75 % nitrogen . Only oxygen supports combustion. Ideally gasoline vapours should me mixed only with ogygen vapours.Nitrogen slows down combustion rate and actually helps prevent detonation.By not injecting nitrogen in vapor state we save space .Then we have plenty of space for essential vapours  .
Burning air is all wrong .We should design engines which  do not waste nitrogen  and give no nitrogen oxydes. An engine designed to mix pure oxygen vapours with gasoline in the vapour state seems more logical ,at least in theory .  

RE: DI Engines

the current gasoline engine burns a very large percentage of the fuel, only a very small amount ends up as CO or HC, etc.
The efficiency has to do with thermodynamics, not air-fuel mixing.

so, you want to carry liquid Oxygen around? I don't think so!

anyway, the Oxygen and fuel act as a heat source to heat the working fluid- which is Nitrogen with some Oxygen in it- what is the flame temp of pure Oxygen and Gasoline? - lotsa luck keeping the pistons and valves alive!)

Jay

RE: DI Engines

Direct injection of petrol (gasoline) a failure?
Citroen and Peugot seem to be using it now-

are they slow learners, or ahead of the pack?

RE: DI Engines

http://www.citroen.co.uk/level4/technicalSpecification.asp?pagetype=c5&lhn=c5

and

http://www.citroen.co.uk/level4/generalpage.asp?pagetype=techcurrent#top

HPi-DIRECT INJECTION PETROL ENGINE

Citroën has introduced a new high-pressure direct injection petrol engine, the first engine of this type to be developed by a European carmaker.

This new HPi petrol engine, which has been developed in co-operation with Citroën's sister company Peugeot, has a capacity of two litres and develops 143 bhp, but it offers specific advantages over the previous generation of petrol units in several other key areas.
Fuel consumption is up to 21% lower.

C02 emissions are also reduced by a similar amount.

More torque is available at low speed.
All this is achieved by using the most advanced technology available today - lean-burn stratified-charge direct fuel injection - and marks the latest step in an ambitious engine development policy initiated in 1998 with the HDi high-pressure common rail diesel engine.

Jay

RE: DI Engines

If you want to increase the amount of oxygen in the intake charge, a common method for doing this is to inject N2O (nitrous).  Pure oxygen is far too dangerous for most applications (welding would be an exception, I guess).

RE: DI Engines

Jay, Don't believe everything you read. A lot of this stuff is 50% hype and 50% BS. I do not think they are even offering a "gasoline" DI engine. In fact Peugeot is starting to switch it's scooters to OCP this year.
" are they slow learners, or ahead of the pack?" You be the judge.

Note excerpts below from recent article:

Automotive News Europe, Nov 19, 2001

PSA's Folz launches quest for quality. (PSA/PEUGEOT-CITROEN CEO Jean-Martin Folz)(Interview)(Statistical Data Included) Sylviane de Saint-Seine.
Full Text: COPYRIGHT 2001 Crain Communications, Inc.

PSA/PEUGEOT-CITROEN Chief Executive Officer Jean-Martin Folz wants European suppliers to match the quality standards of their Japanese counterparts. PSA is learning more about Japanese suppliers in its role as purchasing leader in the new small-car venture with Toyota.

In particular, the 54-year-old Folz urged makers of electronic components to better accommodate the needs of the car industry.

Helped by strong sales in France and the rest of Europe, Folz said PSA would stick to its production and profit objectives for 2001. He also called for a state incentive to scrap old, polluting cars.

Automotive News Europe reporter Sylviane de Saint-Seine interviewed Folz on November 5 in Paris.

Given the current economic situation in Europe and South America, your two main markets, are you revising your production and financial objectives?

With our first-half results, our third-quarter sales and our registration figures for October in France and in Europe, there is no reason to revise our 2001 objectives - that is 3 million vehicles, 4.8 percent operating margin and operating income of E2.6 billion. But that's as I speak. The year is not over.

What about your 2004 objectives set last February - 3.5 million vehicles, 25 new models, annual investment of E3 billion and 6 percent operating margin?

We stick by them.

Assuming times get tougher in the car industry, could we see a revival of government-funded car purchase incentives of the kind we saw in the mid-1990s?

I hope not. I am against state incentives for new cars. They just distort the market. But what would be very useful is a cash incentive to scrap old cars. They pollute much more than new cars because they are often poorly maintained and badly tuned, and because anti-pollution technology has made so much progress since they were built. One could think of a subsidy targeted toward low-income owners of old cars, and its beneficiaries could do whatever they like with the money. They would not have to buy a new car, unlike the incentives we had a few years ago.

Any prospect of such an incentive?

Not at present, although I have been pushing this idea to anyone who would listen. Still, it may be gaining ground. I heard that (VW Chairman Ferdinand) Piech mentioned something along those lines not long ago.

How is the situation in South America? Are you cutting production?

We did cut production in our Palomar plant in Argentina in early spring. We went from two shifts to one. Overall sales in Brazil, which rose in the first half, have been falling in the second half. But we count on producing between 20,000 and 23,000 cars there this year, as planned. Picasso and 206 are off to a good start. For September, Peugeot and Citroen had a 5 percent market share between them. It is the highest ever.

How do you judge the quality of components coming from suppliers?

We have been insisting on quality being considered from the design stage. Co-development of products has been helping to improve quality. However, European auto suppliers still have room for progress compared with their Japanese counterparts.

Isn't the growing use of modules, whereby Tier 1 suppliers assemble components they haven't manufactured, detrimental to quality?

On the contrary, this means suppliers will have to tighten quality control. They will share the same preoccupations as us in managing the quality of their own suppliers. The real challenge is to focus on quality from a very early start in the development process.

It is said that Toyota, your partner in the small-car project, aims to have only two suppliers for any one part. Do you share this goal?

Not particularly. We are not very far from that anyway. Given the restructuring that has taken place in the supplier industry, we have no more than three or four suppliers per component. Each new car model is a chance for us to put them in competition.

Is there a specific problem with electronic components?

Yes. I think electronic component makers haven't quite realized yet we've become a key market for them. Electric and electronic systems represent roughly 20 percent of the cost of a car and that proportion may reach 40 percent in future. They don't seem to have taken that into account and it shows in their prices, which are too high. Moreover, they don't seem to have realized that a car's life span is greater than, say, a mobile phone's.

Do you mean their components aren't durable enough?

I mean they change them too often. They should manufacture each component for a longer period. Sometimes we have to rethink the electronic architecture of a car because the original component isn't available anymore. After all, the car industry is proving a more stable customer than many others. The fluctuations aren't as wild as in other industries using electronics. We're a steady source of cash flow. Electronics manufacturers ought to realize this and be more prepared to accommodate our needs.

Is it necessary to own as much as 71.6 percent of Faurecia? Is it the best possible use of your resources?

One thing is certain: PSA will retain 50 percent of Faurecia for as long as I can see. It's a good investment, with good growth prospects. Our stake in Faurecia exceeds 70 percent because the company needed our help to acquire Sommer-Allibert. One can imagine that this stake will go down following, for instance, an acquisition that would be paid in shares by Faurecia. But there's nothing on the agenda. The basic fact is: We have more than 70 percent of Faurecia and that's not bothering us.

Isn't it a contradiction to hang onto your supplier when so many carmakers do just the opposite and spin them off? Can't this cause conflicts of interest for Faurecia?

No. The real measure of independence is the customer list. In this respect, Faurecia is far more independent than many of those suppliers that have been spun off, such as Delphi or Visteon. Only 25 percent of Faurecia's sales are with us.

Isn't there a sentimental element here? After all, Pierre Peugeot, now head of PSA's supervisory board, nurtured Ecia (which was merged with Bertrand Faure to create Faurecia in 1998) for many years.

I don't see sentiments playing a crucial part in business life. PSA's strategy has been to build what was Ecia into a large supplier group.

Are you going to offer direct injection throughout your entire gasoline engine lineup as Volkswagen says it will do?

No, we haven't made that decision. Direct injection does make perfect sense for diesel, but for gasoline, there are several techniques that can be used to make it more efficient - for instance electro-magnetic valve. Aside from Volkswagen, no one has said it wants to generalize direct injection.

Would you consider a partnership in that field?

No. In principle, we don't enter partnership in research - only in development and manufacturing.

Are there any outside buyers for PSA's diesel particle-filter technology?

We pioneered it and now everyone is busy developing its own. In a year or so, nearly everyone will have one available. They will be second-generation filters, even better performing than what we have now. That's the rule of the game. It is rare for a profitable technology to remain proprietary for a long time. From an industry-wide perspective, I think there is no longer scope for a carmaker to come up with a radically new technology and enjoy a crucial and lasting advantage over its competitors. I don't think we'll see key technological leaps of the kind that Citroen enjoyed with the front-wheel drive, for instance.

Regarding the small car you're developing with Toyota, is it true that it will sell for E7,500?

I can only repeat it will sell for less than our respective entry-level cars [Peugeot 106 and Citroen Saxo], which are around E8,000. I don't think anyone can say what the price for this car will be since it will be launched in 2005. As for its cost, I would not reveal it even under torture.
 
  


RE: DI Engines

Oxygen injection into the induction charge can be made relatively safely.
The low efficiency of reciprocating engines is as mentionned above is  a thermodynamic problem. Lots of heat energy is loss.
The Polymotor plastic engine solved part of the problem.
In more current engines we a a choice to use ceramic coatings which act as  heat tranfer barriers .
The injection of pure oxygen into the fuel charge opens up a new chapter in engine design. Yes the pistons may melt down IF they are not adapted to this set -up. This is why I am talking about new engine designs ,not using unadapted engines.
Now we can be negative and see only the objections and difficulties of this application.We should rather concentrate on ways to do it .We certainly have the technology and heat resistant materials to produce an engine with pure oxygen injection.
I am always amazed by engineers who say : ``it cant be done``Somehow ,they should have been pharmacists or something else which requires less imagination.

RE: DI Engines

I don't think anyone is saying "it can't be done," I think they're saying something more like "you'd blow yourself up if you did it."  Have you looked into the dangers associated with pure oxygen?  The first thing that comes to my mind is that almost anything will burn readily when exposed to pure O2 (including aluminum).

RE: DI Engines

Without opening my thermo books I find myself ina  quandary. On the one hand it seems 'obvious' that the combustion efficiency would be improved if we removed N2 from the combustion chamber, as it is inert (effectively).

On the other hand we have another thread with people extolling the virtues of adding water to the chamber, as an inert working fluid.

So, which is better? I kind of incline towards #2, on the basis that diesel engines ar emore efficient than gas engines, partly because they have a lot of excess working fluid in the cycle (or is it just because they get more complete combustion?).

Cheers

Greg Locock

RE: DI Engines

I thought that the higher compression ratios were the reason diesels were more efficient?

RE: DI Engines

hi, guys
I was logged in as JAYMAEC - now I'll use this identity at home and work.

It doesn't sound like Citroen is abandoning DI for petrol, just not claiming it across the board.
Again, it is listed as an available engine in several models.
Of course, you may be right- but the article you included doesn't seem to support your statement.

mike- I think the diesel efficiency is due both to higher compression, lower pumping losses at part power, and maybe improved thermo cycle (closer to constant pressure expansion?)

cheers
Jay

RE: DI Engines

yeah, I regularly engage the mouth before the brain when posting here...   

I forgot all about the lack of a throttle, the fact that diesels can run lean (and thus use less fuel at low load), etc.  There may also have been some benefit (historically speaking) to the lower amount of smog control hardware attached to diesels.  Proper use of a turbo can further boost the efficiency if a diesel. I'm sure I'm still forgetting some important factors, which is somewhat disappointing since some of my (paying) work has to do with improving the efficiency of diesels...



RE: DI Engines

Wow!

I go away for a couple days and come back to find a lot of interest in my question.

Thanks, especially to Tom, for providing the technical explanations as to why GDI doesn't seem to work.  As I read it, the fundamental physical problem is that liquid fuel droplets are too large and haven't been uniformly mixed.  And the low-sulfur fuel "solution" looks like a bandaid.

I'm guessing the pump and injector technology is not up to snuff.  (But again, it's just a guess and I defer to you guys who know more than I.)  That is, at 150 bar or about 2 ksi the pump is fairly low pressure.  The diesel guys I've worked with brought me in to help them with a slightly radical injector (based on U.S. Pat. 6,279,842) that would operate at 2 000 bar.  The lab model worked pretty well.  The claim is that opening the valve a very small amount at such high pressure works well to atomize diesel fuel.

Anyway, I'm sure my ignorance of the subject is showing!

Charlie

RE: DI Engines

As far as direct injection is concerned,isn't the ficht injection on outboard motors a direct injection.Also would a direct injection with a variable exhaust that uses a O2 sensor in exhaust to adjust the exhaust as far as amount of unburn't fuel not being combusted.forgive the ignorance just asking.

RE: DI Engines

ricktoo,
Todays engines have about 30 % thermal efficiency (not 25%) and the combustion efficiency( what happens in the cylinder) is actually about 90% so you are a bit misled thinking mixing a liquid with a vapour is the problem.  this is why I cannot understand the benefits claimed from a couple of working examples of vapourisers on petrol engines - as they only really have 10% or so to  play with.  Even the best combined cycle turbines only get 50% efficiency or so.

RE: DI Engines

tomthorp, are you on orbital's payroll?  I suspect there will be some servings of humble pie going around in the next year or two with so much DI bashing going on and some of the smartest engineers in the world from citroen puegot and mitsubishi working on this.

for everyone else - Don't forget we are talking about evolution not revolution here - contrary to some opinions here we are not talking about 75% potential increases in efficiency here, but more like 5-10%  i don't read all the magazines but as a practising mech engineer I can offer some sense to some of you guys getting a bit carried away!!!

 

RE: DI Engines

I can envision a day where the inlet valves are replaced by a multitude of air/fuel injectors, at least partially so.

RE: DI Engines

Kimbo 1, No I don't work for Orbital, but I wish I did. I do happen to be a long time stock holder in OE. Check it out:http://finance.yahoo.com/q?s=oe&d=t, http://groups.yahoo.com/group/oec2/messages/?expand=1.

As far as humble pie is concerned, no problem, I've been eating it all my life.

IMHO I think Orbital's OCP low pressure air assisted DI system will be in 50% of the ICE's in the world in the next 10 years. I am trying to be conservative.

Have a nice day, Tom

RE: DI Engines

Caterpillar Patenting Diesel Engines With OCP Fuel Injection
 
We all knew it was only a matter of time before the
diesel manufacturers started using OCP. I say this bexause Mercury Marine is now selling Optimax out boards burning JP-5 to the US Military. Also E P Bassus is converting Tohatsu OCP to burn a variety of heavy fuels to the UK Military. Orbital has known for many years that diesel would work with OCP injectors. Now it is happening. I look for a variety of 2S and 4S heavy fuel applications, both SIDI and CIDI using Orbital's OCP fuel injection systems.

Similar to Gasoline OCP, except air and EGR gasses are mixed and
compressed to the desirable temperature and pressure prior to
entering the OCP injector to be mixed with diesel.
 
 
United States Patent Application 20040112344
Kind Code A1
Wark, Christopher G. ; et al. June 17, 2004

----------------------------------------------------------------------
----------
Temperature control for gas assisted fuel delivery


Abstract
A method and apparatus for atomizing fuel being delivered for
combustion. The method and apparatus includes providing a stream of
pressurized gas, controlling a temperature of the stream of gas to a
desired temperature, and injecting a quantity of fuel into the stream
of gas, wherein the desired temperature is selected to atomize the
fuel to a desired fuel droplet size.


----------------------------------------------------------------------
----------
Inventors: Wark, Christopher G.; (Peoria, IL) ; Choi, Cathy Y.;
(Morton, IL)
Correspondence Name and Address: CATERPILLAR INC.
100 N.E. ADAMS STREET
PATENT DEPT.
PEORIA
IL
616296490


Serial No.: 321157
Series Code: 10
Filed: December 17, 2002

U.S. Current Class: 123/568.15; 123/585
U.S. Class at Publication: 123/568.15; 123/585
Intern'l Class: F02M 025/07



----------------------------------------------------------------------
----------

Claims

----------------------------------------------------------------------
----------


What is claimed is:

1. A method for atomizing fuel being delivered for combustion,
including the steps of: providing a stream of pressurized gas;
controlling a temperature of the stream of gas to a desired
temperature; and injecting a quantity of fuel into the stream of gas;
wherein the desired temperature is selected to atomize the fuel to a
desired fuel droplet size.

2. A method, as set forth in claim 1, wherein providing a stream of
pressurized gas includes the step of providing a stream of
pressurized air.

3. A method, as set forth in claim 1, wherein providing a stream of
pressurized gas includes the step of providing a stream of
pressurized exhaust gas recirculation (EGR) gas.

4. A method, as set forth in claim 1, wherein providing a stream of
pressurized gas includes the step of providing a stream of at least
one of pressurized air and pressurized exhaust gas recirculation
(EGR) gas.

5. A method, as set forth in claim 1, wherein controlling a
temperature of the stream of gas includes the step of controlling a
temperature of the stream of gas to a temperature within a range from
about 100 degrees Celsius to about 500 degrees Celsius.

6. A method, as set forth in claim 1, wherein controlling a
temperature of the stream of gas includes the step of controlling a
temperature of the stream of gas to a temperature within a range from
about 300 degrees Celsius to about 500 degrees Celsius.

7. A method, as set forth in claim 1, wherein the desired temperature
is selected to atomize the fuel to a desired fuel droplet size of
about 10 microns.

8. A method, as set forth in claim 1, wherein the desired temperature
is selected to atomize the fuel to a desired fuel droplet size of
less than 10 microns.

9. A method, as set forth in claim 1, wherein injecting a quantity of
fuel includes the step of injecting a quantity of liquid fuel into
the stream of gas.

10. A method for providing atomized fuel to a combustion chamber,
including the steps of: providing a stream of gas; pressurizing the
gas to a desired pressure; controlling a temperature of the stream of
gas to a desired temperature; and injecting a quantity of fuel into
the stream of gas; wherein the desired pressure and the desired
temperature are selected to provide atomized fuel at less than a
specified fuel droplet size.

11. An apparatus for atomizing fuel being delivered for combustion,
comprising: a source of gas being delivered in a stream; a compressor
located such that the stream of gas passes therethrough and is
pressurized; a temperature control unit located such that the stream
of gas passes therethrough and is controlled to a desired
temperature; a fuel injector for injecting fuel into the stream of
gas after the gas passes through the compressor and the temperature
control unit, wherein the fuel is atomized to a desired fuel droplet
size as a function of the desired temperature; and a combustion
chamber for receiving the atomized fuel for combustion.

12. An apparatus, as set forth in claim 11, wherein the source of gas
is at least one of air and exhaust gas recirculation (EGR) gas.

13. An apparatus, as set forth in claim 11, wherein the desired
temperature is within a range from about 100 to 500 degrees Celsius.

14. An apparatus, as set forth in claim 11, wherein the desired
temperature is within a range from about 300 to 500 degrees Celsius.

15. An apparatus, as set forth in claim 11, wherein the desired fuel
droplet size is about 10 microns.

16. An apparatus, as set forth in claim 11, wherein the desired fuel
droplet size is less than 10 microns.
----------------------------------------------------------------------
----------

Description

----------------------------------------------------------------------
----------


TECHNICAL FIELD

[0001] This invention relates generally to a method and apparatus for
atomizing a liquid fuel and, more particularly, to a method and
apparatus for controlling a size of atomized fuel droplets by
temperature control of a gas for gas assisted fuel delivery.

BACKGROUND

[0002] Atomization of a liquid, e.g., a liquid fuel used for
combustion, is often desired. For example, when introducing a liquid
fuel into a combustion chamber, the most efficient combustion takes
place when the fuel is completely vaporized and preferably when the
fuel has completely and thoroughly mixed with ambient gases also
present in the chamber. The fuel vaporizes more quickly and readily
when the fuel has been atomized to the smallest droplet size
possible.

[0003] Gas assist injectors have long been used to atomize fuel prior
to entry into combustion chambers. For example, in U.S. Pat. No.
4,759,335, Ragg et al. disclose a system which injects fuel directly
into a combustion chamber by the use of compressed gas, i.e.,
compressed air.

[0004] More recently, in U.S. Pat. No. 5,241,938, Takagi et al.
disclose a fuel injector which includes an air assist passage for
atomizing the fuel during injection.

[0005] In U.S. Pat. No. 5,746,189, Kuzuya et al. disclose a gas
assist system in which exhaust gas recirculation (EGR) gas is used
with gas assist injectors. The EGR gas offers the added benefit of
keeping combustion temperature down in the combustion chamber.

[0006] All of the above listed references and others are effective to
atomize fuel to an extent, but may not be sufficient for some
applications, such as when a homogeneous mixture of fuel and air is
desired.

[0007] The present invention is directed to overcoming one or more of
the problems as set forth above.

"SUMMARY OF THE INVENTION

[0008] In one aspect of the present invention a method for atomizing
fuel being delivered for combustion is disclosed. The method
includes the steps of providing a stream of pressurized gas,
controlling a temperature of the stream of gas to a desired
temperature, and injecting a quantity of fuel into the stream of
gas, wherein the desired temperature is selected to atomize the fuel
to a desired fuel droplet size.

[0009] In another aspect of the present invention an apparatus for
atomizing fuel being delivered for combustion is disclosed. The
apparatus includes a source of gas being delivered in a stream, a
compressor located such that the stream of gas passes therethrough
and is pressurized, a temperature control unit located such that the
stream of gas passes therethrough and is controlled to a desired
temperature, a fuel injector for injecting fuel into the stream of
gas after the gas passes through the compressor and the temperature
control unit, wherein the fuel is atomized to a desired fuel droplet
size as a function of the desired temperature, and a combustion
chamber for receiving the atomized fuel for combustion.

BRIEF DESCRIPTION OF THE DRAWINGS

[0010] FIG. 1 is a block diagram illustrating a preferred embodiment
of the present invention;

[0011] FIG. 2 is a block diagram illustrating an alternate
embodiment of the present invention;

[0012] FIG. 3 is a block diagram illustrating yet another alternate
embodiment of the present invention; and

[0013] FIG. 4 is a flow diagram illustrating a preferred method of
the present invention.

DETAILED DESCRIPTION

[0014] Referring to the drawings, a method and apparatus 100 for
atomizing fuel being delivered for combustion is disclosed.

[0015] Referring to FIG. 1 in particular, a block diagram
illustrating a preferred embodiment is shown. A combustion chamber
102 receives fuel and air, combusts the fuel/air mixture, and
exhausts the gases from combustion. The combustion chamber 102 may
be part of an internal combustion engine (not shown), as is well
known in the art.

[0016] A portion of the exhaust gas may be routed through an exhaust
gas recirculation (EGR) system 110. EGR systems are well known in
the art and need not be described further.

[0017] The EGR gas may be sent through a fuel injector 104, in
particular, a gas assist fuel injector 104. Gas assist fuel
injectors are configured to pass a stream of high pressure gas
therethrough. Fuel, in particular liquid fuel such as diesel,
gasoline, and the like, is received by the fuel injector 104, which
causes the fuel to enter the stream of gas. The gas assisted fuel
then atomizes prior to entry into the combustion chamber. It is
noted that the fuel injector 104 may be configured for injection
into an intake port (not shown) or directly into the combustion
chamber 102.

[0018] The EGR gas may pass through a compressor 108 prior to
entering the fuel injector 104. Gas assist injectors typically
require the gas to enter under pressure high enough to overcome the
pressure in the combustion chamber 102. Although the EGR gas may
have enough pressure initially, it may be required under some engine
operating conditions to compress the gas still further.

[0019] In the preferred embodiment, the EGR gas passes through a
temperature control unit 106 prior to entering the fuel injector
104. An elevated temperature of the gas is desired for the present
invention. Preferably, the temperature of the gas as it enters the
fuel injector 104 is within a range from about 100 degrees Celsius
to about 500 degrees Celsius. More particularly, it is preferred
that the temperature of the gas is within a range from about 300
degrees Celsius to about 500 degrees Celsius. Typical temperatures
of gases for gas assist injectors, as used in the cited art
references, range from about 30 degrees Celsius to about 50 degrees
Celsius.

[0020] The temperature control unit 106 may increase the temperature
of the gas to a desired value. However, the temperature control unit
106 may also decrease the temperature of the gas, for example when
EGR gas is used and the temperature already exceeds the desired
value. Although an elevated temperature of the gas is desired to
achieve the desired results, a temperature which exceeds the desired
range, e.g., above 500 degrees Celsius, may cause coking in the
combustion chamber 102, may cause combustion to take place too soon,
and may cause excessive component wear.

[0021] Referring to FIG. 2, a block diagram depicting an alternate
embodiment of the present invention is shown.

[0022] The exhaust gas from the combustion chamber 102 passes
through a turbo-charger 202. In addition, fresh air enters the turbo-
charger 202. It is well known in the art that the exhaust gas passes
through a turbine portion (not shown) of the turbo-charger 202,
which drives a compressor portion (not shown), which in turn
compresses the air entering the turbo-charger 202. The compressed
air is then delivered to an engine as intake air, preferably through
an intake manifold (not shown).

[0023] In the embodiment of FIG. 2, however, a portion of the
compressed air is delivered to the fuel injector 104, for use in gas
assisted injection of the fuel. The compressed air may, however,
first pass through a temperature control unit 106 to achieve a
desired temperature of the air. Although the turbo-charger 202 may
heat the air somewhat during the compression process, it may be
desired to heat the air an additional amount. Alternatively, it may
be desired to cool the air an amount to achieve the desired
temperature prior to entering the fuel injector 104.

[0024] Referring to FIG. 3, a block diagram illustrating another
alternate embodiment of the present invention is shown.

[0025] A source of fresh air is delivered to a compressor 108. The
compressor 108 may be an isolated air compressor used primarily for
purposes of the present invention, or may be a compressor used for
some other purpose as well, such as an air brake compressor on a
large truck.

[0026] The compressed air is delivered to the fuel injector 104 for
gas assist purposes as described above. Preferably, the compressed
air is delivered through a temperature control unit 106 to either
heat or cool the air to the desired temperature.

INDUSTRIAL APPLICABILITY

[0027] Operation of the present invention may best be described with
reference to the flow diagram of FIG. 4, which depicts a preferred
method of the present invention.

[0028] In a first control block 402, a stream of gas is provided.
The stream of gas may be air, EGR gas or some other suitable source
of gas for use in a gas assist injector.

[0029] In a second control block 404, the stream of gas is
pressurized, for example by one of the compressor methods described
above.

[0030] In a third control block, the temperature of the gas is
controlled to within a desired temperature range, for example from
about 300 degrees Celsius to about 500 degrees Celsius. It is noted
that, although compression of the gas is described as taking place
prior to temperature control of the gas, it may be desired to
achieve temperature control prior to compression without deviating
from the scope of the invention.

[0031] In a fourth control block 408, fuel is injected into the
stream of gas as the gas passes through the fuel injector 104.
Preferably, the chosen temperature of the gas results in atomization
of the fuel into droplets having a size of about 10 microns and
less. Without temperature control of the gas, typical fuel droplet
size would range from about 30 to about 100 microns.

[0032] Other aspects can be obtained from a study of the drawings,
the disclosure, and the appended claims. "

Have a nice day, Tom


RE: DI Engines

Greg Locock

"Sure,  But the Orbital engines are usually 2 strokes, so for a given engine size (ALL other things being equal) the torque is doubled, for a given speed.  "

This is something new to me. Knowing that 2 stroke in general has much lower volumetric efficiency if compared to 4 stroke for every induction cycle, will it still be possible to double the torque?

Let me know more about this orbital engine


RE: DI Engines

Azmio, which bit of "All other things being equal" don't you understand?

Cheers

Greg Locock

RE: DI Engines

Greg

When all other things being equal, I understand it as things like bore and stroke, cylinders, displacement to be the same.

Therefore, since 2 stroke doesnot use poppet valve and instead relying more on ports somewhere in the middle, one full stroke would not yield the full induction stroke as the 4 stroke induction stroke.

That's why when you mentioned about doubling the torque, it can only happen when every induction stroke for the 2 stroke engine would yield the exact same volumetric efficiency as the 4 stroke engine.

Well I hope that I have clarified the "which bit of "All other things being equal" don't you understand?" to you.

So back to my question again, is the Orbital engine really doubled the torque when all else being equal?

RE: DI Engines

VAG makes a 2.0 liter 4 cylinder DI engine in Europe that uses a stratified fuel charge.  The US version is due in 2006, but won't have a stratified injection mode due to the aforementioned emissions problems.

RE: DI Engines

thermal losses are reduced by using thermal barriers ie. :ceramics on pistons tops and comb. chambers.Combustion improves and particulates are reduced.
Combining ceramics with high pressure DI for better atomisation will improve efficiency still and cats can be left out as they are only a stop gap measure.

SPEED+++++

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