Originally Posted by Eli
I need to search IamIan's posts and read every one.
Your posts are always so.. Insightful.
I love numbers, and you seem to have a lot of them!
I'm a little surprised by 39% efficiency in non-lean burn. What does it go up to with lean burn, any ideas? Must be close to 50%? Very, very impressive for a gasoline engine.
Can I get a pic of the BSFC chart? I guess one doesn't exist for lean burn? Shame.
Thanks for the compliment
I frequent this forum because I feel similarly about many other very helpful and informed members ... I've learned a great deal from this forum over the years and interacting with all the great people here.
I find myself numbers can help clarify things that can be missed otherwise ... or are too small of a variation to get different people to agree on ... so yeah numbers are my firend
... although sometimes I spend to much time with the numbers / details / theory , and not enough time doing more hands on real world stuff... oh well never enough time in a week.
We do have a very impressive ICE ... even putting all the other HEV .. aerodynamics , Aluminum stuff aside ...
- Gen-1 Honda Insight Engine awards
The Insight Engine won the International Engine of the Year award for 2000.
The Insight Engine won the International Engine of the Year Award subcategory for Best Fuel economy / Green engine in 2000,2001, & 2002.
The Insight Engine won the International Engine of the Year award subcategory for sub 1.0 L Engine every single year it was produced 2000, 2001 , 2002 , 2003 , 2004 , 2005 , 2006
Attached non-LeanBurn BSFC Chart bellow.
We know some quantified things about the Gen-1 Insight's Lean Burn Function ... EPA quote from their testing attached bellow ... but there has been some debate about the phrasing they used ... 8% friction improvement is a direct and obvious ICE efficiency boost ... the 20% improvement phrasing is a bit less clear ... it could mean a 20% wide operating window to get the ~39% efficiency in + the additional ~8% efficiency bonus on top ... or it could mean a 20% higher peak efficiency ... and if it is the later does that mean ~59% peak ( would be unheard of crazy high ) ... or 20% higher than ~39% which would be ~46% ... ~46% efficiency + 8% less friction ... is still crazy good ... that would be better than some diesel engines... but the unknown here is kind of why I would eventually like to get it better defined with some real numbers.... the worst case I see is something like a 20% wide band of the ~39% efficiency +8% reduced friction.
Given the wording that they used about the PERE modeling it at ~0.48 ... that seems to suggest to me they did not just a 20% wider state of ~39%.
Which more directly in context of this thread ... I can do ~77% more work at the higher ~46% point than I can at the ~26% point with the same amount of chemical energy input .... that much variation would allow the IMA path to be much lower efficient and it would still be a net better energy efficiency than pulling the ICE down from it's maximum peak to its minimum low... but the Exact Lean Burn BSFC chart is still not really defined... so that is much more supposition / theory than what we do know from the existing non-lean burn BSFC chart.
46% ICE ~76% IMA = ~35% Net Efficiency.
Any IMA cycle efficiency above ~57% would be better than dropping the ICE from a peak of ~46% to a low of ~26%.
Any BSFC chart g/kwh numbers can be converted to a basic engine efficiency % using the average energy density for gasoline of 13kwh/kg ... of course Gasoline is not a stable product nor is it 100% standardized even at the same octane grade and of course different brand additives can change this as well ... and of course E5 or E10 etc also have different average kwh/kg energy densities.
So take the peak efficiency number from the BSFC chart ... 200g/kwh for the non-LeanBurn Gen-1 Insight invert it to 0.005 kwh/g x1,000 = 5kwh/kg ... then devide by your fuel energy density ~13 kwh/kg * 100 = ~38.46%... repeat for any different BSFC g/kwh number or different known fuel kwh/kg energy density.
Just Keep in mind the conditions the BSFC chart you are using was made under ... if it was made under 100% gasoline ... there will be a slight difference in combustion properties with a E10 fuel instead ... so not only does the E10 have a slightly different energy density , it does not burn 100% exactly the same as 100% gasoline does ... this can be a good thing or a bad thing ... of course depending on how the different fuel burns differently.
Getting a good BSFC of our Lean Burn Engines is on my list of things to do ... there are of course always a few issues to get worked out...
- An accurate real time A/F ratio meter that can be logged / synchronized with other sensor readings / data happening at the same time.
- A lot of Dyno Shops have these linked up to their stuff ... but I haven't found one that does the unusually wide A/F ratios our Gen-1 Insight operates under ... I suspect as the A/F ratio drifts the BSFC chart will change shape slightly with it ... so I expect 15:1 to be slightly different than 16:1 slightly different from 17:1 etc ... and I've seen reports of people using more accurate celebrated A/F ratio meters finding our Gen-1 Insights ranging from as low as 12.5:1 Rich and as lean as 25.8:1 ... that is an unusually wide A/F ratio range ... and when I've called around , beyond the abilities of most dyno A/F ratio sensors.
- I hope to eventually find a correlation between out OEM wide band O2 sensors and specific A/F ratios ... I know the O2 sensors are not linear responses ... and I know the change with operating temperature as well as A/F ratio ... and they have a finite limited response time to changes.
- An accurate real time fuel flow rate meter that can be logged / synchronized with other sensor readings / data happening at the same time... ideally I'd like to exploit some of the OEM stuff already in the car and it would be a standard others could use as well.
- The Dyno needs to be equipped to accurately do the lower power ranges we expect to see ... I'm suspecting down as low as ~5 HP will be needed... many Dyno Shops are designed for hundreds of HP and with the majority of their business coming from the high power 0-60 crowd ... I've had a hard time finding one that is setup to do what I want to do.
- One solution to that I've been looking into is that the key piece the Dyno shop offers that I would need is to have a known torque and RPM not only measured ... but also controlled ... while I like the idea of a Dyno shop for a lot of reasons ... even if I ever did manage to find one equipped to do what I want to do ... by the time I pay for several full days doing all this testing ... I will have spent a good size chunk of money ... and if that good size chunk of money is reasonably close to what it would cost to go other routes and just have my own garage type Dyno that meets my needs , I would be better off having my own type device.
- There are some nice torque and RPM sensors out there that can be shaft mounted ... I think that would be a nice way to gather lots of real world data ... and it would remove the need for a garage which I do not have ... but those are pretty expensive.