# IC engines

1. Jan 11, 2006

### bags

Hey guys ,can u just let me know about the most advanced or developed
IC engine.Plz help.

2. Jan 11, 2006

### Staff: Mentor

Does a hypersonic SCRAMjet qualify as internal combustion, or does the combustion chamber have to be closed at the point of ignition to qualify?

3. Jan 11, 2006

### Cliff_J

How about the BMW VANOS engines, pretty advanced. Also, direct injection gasoline engines are now availale to the public. Electronic control systems have progressed an incredible amount in the last few years too.

What is the purpose of the question?

4. Jan 14, 2006

### Moonbear

Staff Emeritus
bags, it would be helpful if you were more specific in your questions. If you give some context to why you're curious about this, or what it is you want to know about it, or do you just want opinions on what people think IS the most advanced engine, etc.

5. Jan 15, 2006

### brewnog

How about Caterpillar's ACERT Diesel engines?

6. Jan 28, 2006

### joema

There are many ways to measure "advanced": lightest, lowest emissions, best power-to-weight, best power-to-volume, greatest total power, highest efficiency, etc.

However one of the most important is peak thermodynamic efficiency. In that respect diesels are the most advanced. Large ship-based diesels can exceed 50% thermodynamic efficiency, which is incredible.

Smaller automotive diesels if using the HCCI design could theoretically achieve 40% peak thermodynamic efficiency:

http://www.llnl.gov/str/April04/Aceves.html

One of the most advanced mass production gasoline engines is BMW's valvetronic design, which is much more sophisticated than double VANOS:

http://www.bmwworld.com/technology/valvetronic.htm

7. Jan 29, 2006

### Gigabyte111

i would have to say that the most advanced IC engine would have to be one that has been converted to run on bio diesel or on keroscene.

just out of curiosity, has anyone seen or heard of a desile engin that incorpeates the technology that disables 1 or 2 pistions so that they are not firing when at idle? or howabout a diesel hybrid (instead of using a gasoliene engine to power the generator. i havent heard of either of these, but they both seem like they would be a good way to up the MPG's.

8. Jan 30, 2006

### brewnog

A normal Diesel engine will run on biodiesel without any conversion.

Do you mean a Diesel hybrid car? Don't see any problem with this idea, except for the commercial reasons which are currently restricting the sale of petrol hybrids.

9. Jan 30, 2006

### minger

They have been doing this for years. I worked at Honda at the time when they were coming out with their design for it. I believe they first put it on the Odyssey. Anyways, they shut down an entire bank of cylinders when under low load. Basically, it used VTEC-like technology to hold the valves open (so there's no loss of power compressing air), then since everything else is computer controlled, it just cuts spark and fuel.

10. Jan 30, 2006

### Danger

I can think of one, but I might be mistaken. Hybrids apparently start and stop the gas motor when the computer determines that extra power or electrical augmentation is needed. With a Diesel, the warm-up time for the glow plugs would cause a serious lag in starting (wouldn't it?)

11. Jan 30, 2006

### brewnog

Nope, this is on a spark ignition engine, it's pretty common practice now. I don't know of any CI engines which do it though, anyone?

Good thinking. My Diesel engines are all large enough not to need glow plugs (big cylinders = not much quenching of temperature through cylinder walls, and direct injection so no prechambers with large surface areas). Modern direct injection Diesels' glow plugs only come on for a few seconds, even in cold conditions, but I'm sure that with some moderately sophisticated stratification (and perhaps boost limited fuelling, I'm assuming you'd want a small, turbocharged engine for this) you'd be able to get cold start load acceptance good enough to be pretty on-demand. You could use a block heater to keep the engine at a nominal warm temperature whilst not needed, it's a bit of a trick you can use to air cold starts.

Can anyone be bothered to look up what current glow plugs draw, or think of any other methods of quickly starting a cold Diesel, short of immersion heaters or ether? I suppose it wouldn't be too radical to use the engine when starting the vehicle, and then to start it up periodically during motoring, even if not needed, just to keep some heat in it?

Last edited: Jan 30, 2006
12. Jan 30, 2006

### Gigabyte111

here's an idea, devise a system to capture the heat generated by the electric drive moter and then channel that heat (with a liquid that holds heat well) to the diesel engine to keep it warm.

Just a thought

13. Jan 30, 2006

### Gigabyte111

14. Jan 31, 2006

### minger

whoops, didn't read closely enough, and didn't realize we were talking CI

15. Jan 31, 2006

### NateTG

Not necessarily what you think of under hybrid, but there are definitely industrial vehicles (like locomotives) that run using a diesel generator and electric motors. I think this is primarily because the torque characteristics of electric motors are preferrable.
Googling diesel-electric yields, among other things:

Compressed air is a popular method for starting marine diesels.

16. Jan 31, 2006

### brewnog

Yep yep, but automotive applications are more demanding, because when the driver puts his foot down, he needs powere right then, and as Danger pointed out, Diesels have more trouble than petrol engines from cold under these circumstances. Large equipment and locomotives generally use a Diesel engine as their prime source of power (actually generating all the time), rather than switching on and off to supplement batteries as and when required as with a hybrid vehicle.

Indeed, but only as an alternative to an electric starter motor. It's not pumped directy into the cylinders, and does not any more heat into the engine than an electric starter.

I've heard about preheating the fuel, and even the inlet manifolds, but would doubt if this is more efficient or effective than block heaters.

Last edited: Jan 31, 2006
17. Jan 31, 2006

### Gigabyte111

I, in my 12 years of owning many large diesel powered boats/ yachts, I have never in my life encountered a marine diesel started by compressed air, from 15' boats all the way up to a 52' twin turbo diesel powered yacht, have ever heard of a boat started by compressed air, or even have a air compresser on board. i know that for a fact you are required by law (or regulation, not quite sure which) to have atleast two 12v batteries for each engine. it is possible that the lagrer (container ships) ships do this but never in the boats i have had.

zac

18. Jan 31, 2006

### brewnog

I have. They're the noiseist things in the world. Don't be near one without really good earmuffs if one ever starts within 50 yards of you!

19. Jan 31, 2006

### Cliff_J

Is that a compressed air starter in the one scene in the movie "Maximum Overdrive"? As I recall its the newlywed couple being chased at a gas station.

Diesel hybrids are going to happen, but stateside the now highest sulfur diesel is soon to be some of the lowest sulfur diesel and has things all mixed up for the manufacturers. Its not like they don't produce millions of diesel cars for Europe, and there the gas is like $6-$8 a gallon so the idea of a hybrid makes that much more sense.

GM is making diesel hybrid city buses, and some of the heavy-duty truck manufacturers are suppossed to have some hybrid garbage trucks in the works. With both vehicles making frequent stops, its a great optimization for gains in efficiency. I can imagine that once the ROI is attractive on the additional cost carriers like UPS/FedEx/USPS and other fleets will incorporate hybrid into their frequently stopping vehicles.