DI Engines 1

[AlexNeo]

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.

 

[GregLocock]

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

 

[franzh]

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!

 

[mattsooty]

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

 

[FireLover]

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.

 

[GregLocock]

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

 

[tomthorp]

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

 

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

http://www.apriliausa.com

 

[mattsooty]

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

 

[charliebPE]

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.

 

[tomthorp]

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

 

[RBoehne]

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.

 

[charliebPE]

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

 

[tomthorp]

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

 

[riktoo]

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.

 

[ivymike]

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)?

 

[tomthorp]

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."

 

[riktoo]

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 .

 

[jaymaec]

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

 

[jaymaec]

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?