Researchers work toward spark-free, fuel-efficient engines

[Eventer]

When I first read the headline, I thought what's the big deal. I have been driving a spark-free, fuel-efficient engine for 143,000 miles and 7. 5 years.

Researchers work toward spark-free, fuel-efficient engines

Lead-in to the story on physorg.com: In a gasoline spark-ignition engine (left), combustion begins when a mixture of fuel and air is ignited by the spark plug. In a diesel engine (center), combustion begins when fuel is injected into hot, highly compressed air. In a homogeneous charge compression ignition engine (right), well-mixed fuel and air are compressed until combustion occurs at multiple points throughout the combustion chamber.

 

[CSkal]

I thought the concept was interesting. I saw the same thing in ME magazine in the last issue. And guess what? There is research being done on this at Purdue University with a (ta-da!) B6. 7 Cummins for the test bed! How about them apples?

 

[AKaiser]

I thought the concept was interesting. I saw the same thing in ME magazine in the last issue. And guess what? There is research being done on this at Purdue University with a (ta-da!) B6. 7 Cummins for the test bed! How about them apples?

I like them apples alot!!! Not an engineer, but I did graduate from Purdue (College of Agriculture). That was over 10 years ago, and Biodiesel was in it's infancy.

 

[LMcCary]

Multiple injection and firing points is old news. Cat and Cummins have been doing this for many years now. In Cummins can now do Five injection points per power stroke.

 

[Vaughn MacKenzie]

Multiple injection and firing points is old news. Cat and Cummins have been doing this for many years now. In Cummins can now do Five injection points per power stroke.

That's not the same as what is mentioned in the article. . . it's about combustion starting from several locations within the combustion chamber simultaneously, not multiple injection events which occur in sequence. Also the fuel is injected together with air.



Vaughn

 

[cj hall]

fuel and air injection

Wow

Things get out of control fast.

So if this is right then not only will we be messing around with the fuel side now we can start to mess with the air side

Pure OX instead of air ,toped off with a hit of propane or ???? gas then just for the fun of it a charge of NOX



JUST THINK OF THE CAN OF WORMS THIS WILL OPEN UP.



hope we can still drive the things!



Just think what it would be like if we all stayed at a Holiday Inn last night !!!!!!



cj hall

 

[LMcCary]

I guess that you do not understand multiple injection events. Of course we call it rate shaping. The only difference that I can see in this poorly written article, that they are using gasoline other than diesel. It really does not matter though, gasoline is not effiecent as diesel. It is more hazardous and polutes the air worse than a diesel with DOC/DPF treatment.

 

[JoeBioDiesel]

LM,

These HCCI engines aren't using multiple injection events. The fuel on them is brought in during the intake stroke, like a gasser, where the intake stroke on a diesel brings in only air... as I'm sure you know. Another difference from the gassers is that in HCCI engines they usually try to have the fuel vaporized, and not just atomized when it enters the cylinder.



Here's the problem with HCCI engines, at least as far as I'm familiar with them. Because there is very little control over when ignition occurs, they run quite efficiently only with a fixed load and RPM. They might make decent hybrid motors, but offer little promise as car/truck engines in the near future because of those limitations(no control over ignition timing). Attempts have been made to use variable displacement engines to improve them, but those add an entirely new set of problems. HCCI engines have been around for a while, and they make the news every time someone takes up new research on them. I'd like to see someone drop one in a hybrid and see how it works out.





Joe

 

[Gary - K7GLD]

LM,

These HCCI engines aren't using multiple injection events. The fuel on them is brought in during the intake stroke, like a gasser, where the intake stroke on a diesel brings in only air... as I'm sure you know. Another difference from the gassers is that in HCCI engines they usually try to have the fuel vaporized, and not just atomized when it enters the cylinder.



Joe

Seems I remember quite some time back - probably 40 years ago - that one of the "Miracle gas MPG" devices used some sort of heating element in the fuel line ahead of the carb to heat and vaporize the gas for greater combustion efficiency - sounds like a new variation of some sort has returned to the present day...

 

[rbattelle]

HCCI is an interesting concept - sort of a hybrid CI/SI engine. What I wonder is, using gasoline as a fuel how do they control detonation? Actually, the combustion characteristics on these sound suspiciously like detonation to me.

That would imply the need for an extremely strong engine structure, since peak pressure would be enormous. Good for MEP, I suppose.

Ryan

 

[Mundgyver]

Heating the gas works to a point. With fuel injection the temp can go higher than with a carb. Anybody remember a thing called vapor-lock on a gas engine.



I know if you can heat diesel fuel to about 185* to 200* before injection, you will get about a 30% improvement in fuel burn and economy of operation. The problem is that the VP-44 won't handle the heat at is dies when you get up around 160*. There are industrial application on gen sets and construction equipment that have different fuel injection pumps where they are able to get a solid 30% gain by heating the fuel to 185*.



I had looked into this a few years ago and had a heck of time finding out what and why Bosh would not answer my questions about heating the fuel before injection. They were really reluctant to point of not wanting to tell me anything.



If the electronics board for the VP-44 was mounted off the VP-44 for separate cooling, I would ramp the temp of the fuel up and give it a try. I just do not want to kill the board which in turn kills the VP.



That is what I have found out.



A gas that runs like a diesel in a steady state sounds like it would be a good hybrid experiment though. Should be fun to watch this over the next few years.

 

[AKaiser]

Any time you increase the heat going into the chemical equation, you get a faster, more complete result. That's just simple physics and by derivation, chemistry. Heat increase in equals a corresponding heat increase out. Cannon propellant rate of burn increases with increase in temperature, which causes range increases with propellant temperature increase due to the resultant pressure increases and increased rate of burn. This is one of the reasons engines run more efficiently at operating temperature.



Keep your powder dry!

 

[ELaslo]

Check this out. 6 stroke engine.

Inside Bruce Crower’s Six-Stroke Engine - AutoWeek