Why no more lean burn??

[gone-ot]

MetroMPG -- agreed! HCCI is 100%-time lean-burn, but with diesel-like efficiencies due to high CR and high in-cylinder temps (ala' diesel). The problem (so far) has been maintaining drivability across the whole idle-to-high-rpm range, which (so far) has been only partially compensated by reverting to spark-plug ignition at partthrottle speeds where the very-lean AF mixture makes sparkplugs almost useless.

[user removed]

If you want to see the future of "lean burn" check out Transonic Combustion. Supercritical preheated fuel under ultra high pressure to prevent spontaneous ignition, fed into the cylinders at various points during the combustion stroke itself is the future of "lean burn". which is not really lean burn at all. That was just the limits of technology available to Honda beginning in the 1970s and developed into the 1990s. The future developments will make it look like archaic technology. Quantum leaps in ignition, combustion chamber design, and injection sequencing will be the next generation. No spark necessary and multifuel capable. The next step will be engineered fuels that eliminate combustion byproducts, which when combined with transonic type injection will propel IC into the 22nd century, possibly devoid of ANY aftertreatment due to efficiency of combustion, the way it SHOULD have started 50 years ago.

When combined with the next generation powertrains and particular attention to reducing vehicle weight, you will see 100 MPG combined in the next 10 years. Aero will be an integral part of the total vehicle with powertrain and engine systems that can truly take advantage of lower average total drag values.

regards
Mech

[RustyLugNut]

Originally Posted by slownugly

Rusty- so let me get this straight. If weight was taken out of the equation on a new gasoline non-hybrid to equal the weight of my 2000 lb vx then the return would be the same or superior to the lean burn technology? They are making new cars that are lighter and more aerodynamic and they still don't touch the vx. Speculation or educated guesses about a certain drivetrain in a lighter car is not enough to sway my opinion.

I have tested my vx with 650 lbs and mileage dropped 3-4 mpg from my average. (to 49mpg from an average of 51-53) That's about 2750lb curb weight. If I increased the weight to 3000 lbs I highly doubt it would drop below 45. This makes me want to try it. I'll drop a small book Chevy in the backseat haha.

One of them is emissions. They have upped the Bin requirements since 1993. Your Honda would fail miserably.

But, this basis of current technology will allow lean burn to make a reappearance as other posters have pointed out.

I am not saying YOU should go out and buy a new econo car, I am simply saying the level of technology allows the average person to purchase a vehicle from a range of many, that can easily return 35 to 45 mpg in normal driving - even with all the comforts of Bling current customers require.

The fuel savings between a 45 mpg vehicle and a 55 mpg vehicle are actually quite small. But, multiply that by millions of new vehicles purchased, it is considerable. But, first steps first. We need to get people out of their 22.5 mpg cars and into the 45 mpg cars. THAT is a HUGE savings for society. The lack of appeal for a car like your old VX was why it didn't sell in massive numbers. We need these new 45 mpg cars to reprogram society away from the SUV commuters of a generation past.

[Cobb]

A quick trip to the machine shop should make that no problem.

Originally Posted by MetroMPG

Mazda says:

So says Mazda's chief exec for powertrain development, Mitsuo Hitomi.

Though he's talking about HCCI petrol engine development, not a "lean burn mode" in an otherwise standard engine.

http://www.autonews.com/article/2014...on-skyactive-2

[BLSTIC]

Originally Posted by pgfpro

In the future I think we will see Stratified 'Ultra Lean Burn Engines" at 65:1 A/F ratios running "Gasoline Direct Injection" and "Spray Guided Piston Injection" in conjunction with new Turbo Charger technology in the forms of "Turbo Compounding Motor Generation Units Heat" and dual stage high-pressure/low pressure turbos systems.

Turbos like This?

[twinair]

Originally Posted by slownugly

Gettin back on topic, if they do achieve extremely lean afrs above 50:1 what effect will that have on performance?

You pump a lot of not-needed air and increasing frictional losses unnecessarily. These additional frictional losses could hardly benefit fuel economy.

[rmay635703]

Originally Posted by twinair

You pump a lot of not-needed air and increasing frictional losses unnecessarily. These additional frictional losses could hardly benefit fuel economy.

??? If the AFR is not induced by ramair or by a turbo...

You are apparently saying that it is much more efficient to place a restriction in the intake?

If you are saying we want to force leanburn with a turbo then I agree with your statement.

[twinair]

No, I'm saying that it is more efficient to use a longer gearing (run the engine at a lower rpm) or downsize an engine than to pump over 3 times more air than is needed.

[minispeed]

Originally Posted by slownugly

Rusty- so let me get this straight. If weight was taken out of the equation on a new gasoline non-hybrid to equal the weight of my 2000 lb vx then the return would be the same or superior to the lean burn technology? They are making new cars that are lighter and more aerodynamic and they still don't touch the vx. Speculation or educated guesses about a certain drivetrain in a lighter car is not enough to sway my opinion.

I have tested my vx with 650 lbs and mileage dropped 3-4 mpg from my average. (to 49mpg from an average of 51-53) That's about 2750lb curb weight. If I increased the weight to 3000 lbs I highly doubt it would drop below 45. This makes me want to try it. I'll drop a small book Chevy in the backseat haha.

None of the new cars now will be compared to old cars with an "apple to apple" cause the EPA tests are different. They use a factor to estimate what old cars would have got, but how accurate is that going to be for every car?

So take a look at this users fuel log, Mitsu Mirage 59.5mpg lifetime, about the same weight as your civic. It's rated at 37 combined vs the Honda VX at 43. The fiesta 1.0l turbo is rated about the same as the Mitsu although I didn't find any user data. And those are the closest cars to the sub compacts of the 90s and each is about 8cu ft more interior space, 4 doors, the sedan fiesta has 1 cu ft less cargo and the Mitsu has 4 cu ft more, and both of them do it without lean burn. Using my 19000mi/year and $5.0/gal for gas presets at sticker EPA both the mitsu and fiesta only come out to $350/year more for gas.





As for ROI from the design stand point, nothing will beat an EV or parallel hybrid. At ecomodder a lot of us chase aero mods first because as others have said it's "the low hanging fruit". To a manufacture who wants to bring down their CAFE an EV or hybrid is the low hanging fruit, no engine, no emmisions and if it shuts off the engine 10% of the time it's an instant 10% reduction in fuel consumption and emissions. If you can figure out how to get more energy density into the batteries you can shut down the engine more. The best part for the car makers is there are a lot of other companies trying to figure that out taking all the risk and fronting all the cash that will try to sell that technology to them when they develop it. If that technology lets someone sell a car with Tesla range/charge time specs for $30g they will be laughing all the way to the bank. If they wanted to develop lean burn they would have to take all the risk and front all the cash and then if it worked come up with an expensive marketing campaign to convince the public it's worth buying.


I think the future of the ICE will include mild hybrids as standard for a long time coming, what's the point of lean burn at idle as others have talked about when you can just shut it off and run all the electrics, ac, heat without the ICE?

[steveo539]

Wow, good stuff here. Some of it way over my head though. I'm new to this site and just recently bought my second HX. I'm a small guy so the small cabin does not bother me one bit. Most of the time it's just me riding around in this buggy. My rather large, tall friend has another opinion however. The road noise is a bit loud but I can live with it. I am trying to source a MPGuino gauge for my car still so I'm not sure what my actual millage is. I'm only on my second tank of fuel so have no reliable data yet. My old HX gave me a pretty consistent 40+ MPG cruising at 65-70 MPH. Best tank I ever got was 46MPG. I can see Slownugly's point about spending $2-3K on a stock, 15 year old car, and get 40+MPG "right outa' the box". Makes it hard for me to justify $25K+ for a new hybrid that gets roughly the same MPG.
I'm curious about the "NoX" emissions. Are those limits in PPM (as a percentage of the exhaust) or total number of parts out the exhaust pipe? If PPM only, doesn't the fact that you are burning less than half the number of gallons of what the average vehicle on the road burns, count for anything?