http://world.honda.com/HDTV/news/2003-4031127a/

i didnt think that was enough fuel to even ignite, but i guess since its compressed it doesnt matter. wouldnt running that lean, even at cruising speeds, hurt something?

 

All direct injection engines can have lean fuel mixtures. Honda seems to be the highest at 65:1 but others run up to 50:1. It's impossible to ignite such a lean mixture (even 20:1 is already extremely hard). To get around this, the mixture is kept rich around the plug and super-lean in the rest of the cylinder. The rich mixture near the plug ignites normally and ensures proper combustion of all the remaining mixture in the cylinder.

Honda does this by putting a small chamber in the piston (as seen in the video). This concentrates the fuel mixture in a small area for easy ignition. VW/Audi does this by using tumble flaps and careful control of air turbulence to ensure a rich mixture around the plug electrode. Different systems, same results.

 

ahhh...thanks for the info! it does make sense now that you've explained it.

 

Looks like a diesel engine with a TB and spark plugs.
I wan't to know what the EGT's are becasue on our engines if you run lean you will burn valves, they fixed it with these some how.

 

Bet ya those injectors and fuel pump isnt cheap. I wonder if the cavity in the piston is good for turbo and nitrous apps. Cool vid though.

 

Lean, doesn't necessarily burn valves.
However, some people will try to
make a 'thermally inadequate engine',
safe to use at WOT, by pumping in so much fuel,
that the cylinder gets less oxygen, so it runs cooler.

 

Thing that always stopped these engines from being used in the US in the past is that the lean burning still produces a lot of NOx vs. a more traditional engine. The video says they have done some stuff to "reduce NOx emissions" on the new engine, whatever that means.

The fact that all the specs are still listed in Metric units makes me wonder if they have "reduced NOx" to the point that they could sell it here.

The US may gobble up most of the gas in the world, but we also have the tightest emissions standards.

 

Our emissions standards are bad, but there are other places in the world that are just as bad, and places in the US where emissions doesnt matter to anyone. Comparing California to the rest of the world - there are still places that are just as bad.

On the subject at hand, burning that lean (and controlling it) has advantages. But the question is, for the added efficiency in the mpg department, what is the cost offset to the vehicle? It's the same with many things. The gains arent attractive enough to legitimize it against the costs.

 

Well, everything is expensive for a Honda. but no, the injectors and fuel pump aren't a ridiculasly high price? why would they be? Or are you still talking about a diesel engine. In that case, they start at like $400

 

It takes fuel to make HP. There's no magic way to create x amount of HP without using y amount of fuel. Running an engine at some super lean A/F also means the engine is only going to produce a very small amount of HP.

At reasonable cruising speeds (say 100 km/h) you need to produce enough HP to get around rolling resistance and wind resistance. If you ran your engine at 65:1 A/F, you'd probably generate enough HP to get up to 25 km/h. At 100 km/h, lean burn engines usually run an A/F of anywhere from 16:1 to 20:1. Any leaner and they won't produce enough HP to keep moving. Still, running an engine close to 20:1 will give you a significant increase in mileage.

The only time a direct injection engine can actually operate at super-lean A/F ratios is in city traffic at low speeds or under slight deceleration.

Still, saving 20% on your fuel bill is still worthwhile.

 

no, not neccisarily.

you are trying to increase power using the same amount of gas, or in this case, same power- less gas. its called efficiency and more specifically, BSFC.

more compression = same gas consumption but more power.

running leaner = more power, less gas

infact, some race engines i have worked around shocked me with their fuel injection choices. they are so much more efficient than street cars, they use smaller injectors.

750+hp, low fuel pressure, and 4xlb fuel injectors and a moderate duty cycle? thats unpossible

 

Just figure because of the high pressures.

 

Cruising speeds here in japan are going to be 50mph tops if you keep to the speed limit. Don't think you will get killer gas milage in the states flying down the interstate.
Don't even think about taking a 4-cylinder econ-o engine and try and turn it into a race engine, you will end up with neather. We have been over this before.
This is why most of us have V8's or larger ci V6's, we want power, handeling and style not 36mpg.

 

I couldn't see the add very well, but it looked like 117hp out of a 2000cc engine. Doesn't sound very HP to me.

 

thats where the LS1 comes in...in the vettes anyway. my friend gets 34 mpg quite often!