Laser Ignition(Spark Plug Replacement)Boosts Efficiency 27%

[flathill]

Guys with Audi RS5s on this forum I follow are having their heads cleaned with walnut shell blasting every other oil change at the tune of $800+ a pop. It only makes a huge difference at the loads these guys are regularly pushing.

This is when you know its time to buy a used P85+ or new P85D

It's like having to change the oil and check the valves after every race on your dirt bike. Buy a BRD/Alta Redshift already and stop wasting all your time dicking around.

Combustion/Detonations are still needed but not for the average land based vehicle

 

[Ohbse]

Cool idea but bullshit results. 27% of what is the key question to be sure.

Subaru BRZ/toyota 86/scion FRS uses both direct and conventional port injection and is this unlikely to suffer from the same fate as the Audi's.

 

[Dauntless]

27% what ?

The typical ICE is at 33%
So does this make it 60% ?
Or 1.27*33 = 42% ?
Or has the (i dont know) 10W taken by the ignition system been reduced to 7.3W ?

Or does the laser make it possible for a cooler more complete burn, creating the possibility of over 100% being possible because there's a new definition? The laser is supposed to help in the ignition of fuels more difficult for the spark plug that can withstand a higher compression ratio without self ignition. As compared to the 100% for gasoline in an 8.5:1 compression ratio you're greatly exceeding 100% potential.

if more than a small percentage of the fuel injected comes out unburned, which is necessary for cooling, something's terribly wrong. Lasers are neat though! I wonder how they're keeping the optics clean and cooling the valves/pistons.

I always say if there's a way to not create the heat in the first place, the efficiency goes up.

Just because fuel is all burned doesn't mean it's highly efficient. That just means it is good on emissions.

Or worse on emissions. An engine running too lean runs dirty. Carbon Monoxide can go UP.

The way I understand it is working is that with the laser focalized on the center of the combustion chamber, this make the explosion to start from the middle and expand in all direction at the same time witch reduce the explosion time and increase peak power of each explosion.

Next problem is that to make a spark do they need a femtosecond laser? :lol: because the peak power required to ionize the air and make a spark usually require one of these complicated laser....

it I seasy to imagine a beam to focalize somewhere.. but it does not mean it create heat at this area...

To create a spark they need insame power with many digits!! during femtosecond duration scale...

Well Doc, you've convinced me. Let's put you to work at the Government lab. Here's a guy whose Ph.D. dissertation was on laser ignition for natural gas engines.

http://www.processeng.biz/docs/laser_Konferenzbeitrag_IFRF_proceedings.pdf

http://www.osa.org/en-us/meetings/topical_meetings/3rd_laser_ignition_conference/

“Our system delivers low peak power – less than 1 kW – to a miniature passively Q-switched laser that it converts to a high peak power output of a few megawatts suitable to be focused down to approximately 100 GW/cm2 to create a laser spark,”

“Our laser spark plug is a passively Q-switched Nd:YAG laser, 1 in. long, pumped coaxially by a diode laser source through a fiber optic,” Woodruff said. “The laser pulse is aimed through a thick fused-silica lens that also serves as the pressure barrier. With diode laser pumping, the energy cost is very similar to an electric spark system.”

“We currently hold a patent on the optical delivery system, which could be used to reach multiple cylinders on an engine with the proper timing,”

“Others have investigated using a high-peak-output laser to simply deliver the high-peak-power pulse through an optical fiber or other type of waveguide, Some have considered actuated mirrors that swing in and out of the laser path to redirect it to different locations.

“In the early development phase, most people in the consortium were using laboratory-scale high-peak-power lasers that were either directly connected to a single cylinder, or they were bouncing the laser beam across the room and into the combustion chamber.” This was carried out, he noted, mainly to obtain reliable data as other methods were being developed or considered.

“A Japanese group is working on ceramic Nd:YAG lasers, which may help lower the cost of the YAG component,”

 

[Punx0r]

Don't get confused - an ICE is a *thermal engine* the power it produces is directly proportional to the heat energy released by the burning fuel. The idea of a "cool burn" is nonsense.

 

[MrDude_1]

Don't get confused - an ICE is a *thermal engine* the power it produces is directly proportional to the heat energy released by the burning fuel. The idea of a "cool burn" is nonsense.

Dont oversimplify it either... If I burned all the fuel slowly in the chamber, the pressure (and therefore power) is lower than if I burned it all at once at the ideal timing. The ICE is a PRESSURE engine, in that it converts the pressure differential into energy. You could run an almost identical piston engine by injecting pressurized air if you wanted.

 

[Dauntless]

Don't get confused - an ICE is a *thermal engine* the power it produces is directly proportional to the heat energy released by the burning fuel. The idea of a "cool burn" is nonsense.

So when I was a LICENSED teenage smog mechanic, (NOT 'Tester') the Bureau of Automotive Repair telling us we were looking for a cooler burn was "Nonsense?" That the lost horsepower of those engines of the late 70's-into the 80's that were hotter and using more gas than their predecessors behaving 'Nonsensically?' (Wait a minute, I almost want to agree with you on that part. . . .) Are you also saying it's a good thing I got out of that around age 20 and got into Television? Sometimes I think I might have been better off if I kept working on cars.

So when I was a kid I got hold of some really interesting information Dad brought home from work. Was it a company newsletter, some memo they sent out for whatever reason, I don't recall. But he worked for an aerospace company that built some of the most famous planes of World War II, so I'm sure they knew plenty about the government effort to mix water with gasoline during the war.

Dang, I first became a history nut in 5th grade, I was already reading about the aviation of WWII and had found references to the effort but no real info. This was telling about how they thought 18% would be just right, that the air cooled radial engines would benefit more than the inline liquid cooled because of the cooler burn, etc. There wasn't any explanation of why they thought there was a way of mixing something with water that would change the properties enough that it wouldn't just collect at the bottom of the fuel tank. I'm familiar with nitrogen making water heavier, but what would make it lighter?

So they shifted their efforts to water vapor injection. Not sure why this didn't work out as planned, the article didn't say. But water vapor injection found its' way into aviation. Look it up, before you jerk your knee in response. Oh, I'm sure SOMEONE was reading this with hopes of a another joyusly contemptuous "Nonsense," I think that one has tasted enough foot for one day. (I'd like to think most of you realize that the people who say "Nonsense" wind up embarrassed a lot.)

Oh, I could go on about my own experiments when I bought a lawnmower that was older than I was and got it running again to build a go kart, but it was a vertical crank and a 12 year old could barely learn how to build a kart with a more conventional horizontal crankshaft, so instead I was in the lawn mowing business to make enough money to just buy what I need. Which greatly pleased my mother, who simply took the money. . . .

But if she only knew the risks I was taking with her cash cow when I was wasn't mowing. If you're thinking you can do this vapor injection with a spritzer bottle into the carburetor, well, I can squash that one for you. (Hey, when you're 12 you gotta try these things out.) By the time I was in college I had come up with something that sort of worked on my car, my gas mileage went up (A little) and it sort of seemed, you know, jumpy compared to before. But there were downsides and I took it off. Some 50,000 miles later I concluded the valves were going, in fact they had become--- well, not conventionally toasted, but there was a problem. (Oxidized?) I wonder if my little experiment had anything to do with it.

Ah well, I'm at least bound to know more on that subject than anyone reading this, because I did what reading I could and I conducted experiments. For some goof to say "Nonsense" would be, well, I won't use the word but. . . .

It IS funny to me that this was the second ridiculous use of "Nonsense" that I was subjected to in one day. The first has to do with my efforts to get my own gearhead for a tripod. Expensive thing normally, but it's a wonderful way to shoot. Basically much like the way they used to aim the big guns. When I first started telling people of a gear head well under $1,000, those who are always ready to air out their tonsils said "Nonsense." But you see, there's this place in India called Film City, it's like Disneyland to those of use in Film and Television. India (AKA Bollywood) is the filmmaking capital of the world, at least in numbers of films made each year. Film City markets amazingly cheap equipment.

So last year, once I'd managed to see one of these heads and concluded it was worth the investment, they seemed to vanish from the market. eBay sellers were saying it was discontinued. A few others said "Darn, just as *I* was about to buy one." You know what I could have said to THAT.

But I did say I was going to find a way to get one anyway. And those perpetually outdoor tonsils said "Nonsense." Today I said it was on the way from Film City, India; someone said "Nonsense." But I didn't get where I am by saying "Nonsense." And the people saying nonsense don't seem to get where I am. I do enjoy saying "I may not be getting ahead, but I've gotten ahead of YOU."

Ah well. the real fun is in asking "What is the flash point of water?" The over oxygenated tonsils sometimes get so vociferous in their feined expertise they irritate some real scientist into explaining what's wrong with their particular jerk knee response at that moment. . . .

I just gotta put up another picture of what this thing will look like in action. Brings a whole new meaning to the idea of a 'Cool Burn,' eh?

 

[Punx0r]

Dauntless, you can have a cooler burn by altering the fuel:air mixture. What you can't have is the same mixture, producing the same or greater power but somehow burning cooler.

Dont oversimplify it either... If I burned all the fuel slowly in the chamber, the pressure (and therefore power) is lower than if I burned it all at once at the ideal timing. The ICE is a PRESSURE engine, in that it converts the pressure differential into energy. You could run an almost identical piston engine by injecting pressurized air if you wanted.

Point taken that the issue is complicated by timing, however the point stands: It is a pressure engine but the pressure differential is produced entirely by the temperature differential. The fuel:air charge contains a fixed amount of available energy, whether you burn it all in a pico-second or in little bits over a period of 10 seconds makes no difference. The practicalities will be different - an engine working on a 10 second burn time would be very slow, and the pic-second one would destroy itself from peak pressure and piston acceleration. It's just the difference between a short, hard push and a long, gentle push.

Going back to the original point: the claim the laser unleashes all this extra power from an engine by burning the charge faster than a progressive burn from a spark plug sounds like nonsense. The burn-time on an ICE is already more than fast enough. A faster burn would just give a greater peak cylinder pressure but the same average cylinder pressure, producing no more torque.

The reason diesel engines can't spin as fast as a petrol engine is due to the much lower speed at which the fuel burns. This is just not a limitation on petrol engines.

 

[MrDude_1]

Going back to the original point: the claim the laser unleashes all this extra power from an engine by burning the charge faster than a progressive burn from a spark plug sounds like nonsense. The burn-time on an ICE is already more than fast enough. A faster burn would just give a greater peak cylinder pressure but the same average cylinder pressure, producing no more torque.

uhh.. no. thats incorrect.
Thats also why some motorcycles and high performance cars have two spark plugs... two flame fronts burn faster. This becomes important if you have a large bore. also, you can get more efficiency (and therefore power) out of the same amount of fuel by burning all of it at once while the piston is still at the top, rather than burning it as the piston is moving down..
the largest problem with two spark plugs is the effects of the two flame fronts converging.

also, there is a diff between burning and detonation.
and you dont have to go to picoseconds multiples of 10 miliseconds is fine.

 

[Punx0r]

That was just a daft example with a number plucked from the air

Motorcycle engine with two plugs is an interesting example as it's almost certainly for the sake of performance. Am I right in guessing these engines are over-square and rev to very high speeds? My only previous knowledge of a car engine is the Alfa twin-spark, which I was told by an automotive engineer was intended to enable lean-burn (before catalytic converters killed that idea).

Thinking about it more (integrating pressure over the stroke), you're right: average cylinder pressure is different depending on burn speed.

However ( ), I still remain unconvinced that a faster burn speed from simultaneous ignition of the charge by a laser will offer a significant advantage to the average car petrol engine. Perhaps I'm wrong...

 

[Drunkskunk]

Faster burn won't benefit most engines now. the engine would need to be designed for it. shorter stroke and higher RPM motors running higher compression ratios and correct valve timing can benefit from faster burns. But most common existing engines would be destroyed by just increasing the burn rate, so this will lead to a new class of engine.

As for water injection, it's a neat idea for a quick power boost, and works in some ways like NOS. The main benefit is that the water cools the combustion chamber allowing a leaner burn at higher ignition advance without detonation. The benefit isn't from cooler combustion, but from not developing hot spots that cause detonation. Water injection also increases the volumetric efficiency of the intake charge by increasing the intake charge density. That means you can cram more air and fuel in per stroke, burn it leaner, and get more power per stroke out of the engine. There is also a small benefit from the water being flashed to steam during combustion which increases the combustion pressure. The down side is the steam strips the oil from the valves and rings, so long term use would damage the engine. That makes it only good for short boosts of power.

 

[Punx0r]

I was once told "water injection takes up space that should be given to fuel. Just build and tune the engine properly so you don't need water to suppress detonation".

I guess it has advantages if you've already gone to the ragged edge of what's possible with your engine and fuel.

 

[friendly1uk]

I guess it depends how far your going.