Hi MGBGT,

I may be able to answer some of your questions.

First, California vs US: CA specifies petrol production parameters over and above maximum sulfur content. Since the auto manufacturers have to submit their cars for CARB (local authority) testing, they are probably using CA petrol, and getting results that cannot be generalized to other parts of the country. Same cars, different petrols. That said, I think it is fair to say that if your local petrol has sulfur content as low as that sold in CA, you can use CARB's results, since AFAIK, sulfur is by far and away the major player in determining how effective the post combustion emission control devices are.

Dirty Civic/Clean Civic hybrids:Same engine, but Honda has set some of their production to 'lean burn' air:petrol mixture ratios to improve mpg at the expense of increased emissions. AFAIK, only the cleaner autos are sold in CA; it might be possible to pick up one or the other outside CA, but I am not sure.

Prius II emissions: I'm sure Wayne will post his references. His comment about margins peaked my interest
I posted in the Share section NREL data that is quite detailed on the Prius I. I have read that the Prius II is even cleaner, but that is as close as I have ever gotten to real numbers for the Prius II. NREL uses it's own testing format that is different than EPA or CARB. They did also test the Insight, so you could come up with a fudge factor if you can find the Insight numbers from one of the other agencies. I personally am too lazy, and so use the NREL test that is closest to 50 mpg.

One last point: None of these testing formats include idling AFAIK, so all cars that do not turn off the ICE at stop are getting a free ride, as it were.

 

Hi EricGo:
___It is not just a lean-burn/non-lean burn issue. It is a MAF sensor and much more robust CAT’s on the PZEV based Honda’s that make them cleaner then their LEV-II based siblings. ___The Free ride shows up in the fact that the Prius II excels at the EPA test cycle(s) but the real world FE data shows a distinct disconnect vs. the Honda’s which do match or beat the EPA estimates on a much higher percentage basis.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Wayne,

Are you suggesting that FE differences in real-world driving compared to EPA can be extrapolated to imply emission differences of the same order ?

I see no reason to conclude this. Data, please.

Addendum: BTW, I looked at the GH db, and found that 31% of civic hybrids do 48 mpg or better, compared to 45% of Prius II's.

So there !

 

That is interesting. Care to take a guess what kind of emissions a lean burn civic with the PZEV's after treatments would produce ?

Or how much mpg hit the the MAF and 'more robust' CAT cause ?

 

Hi EricGo:
___I am not suggesting anything. The EPA City FE and Emissions ratings/scores are calculated using the FTP75 test cycle. They bag the exhaust and analyze it for its constituents. More then once in most cases. The EPA does not test all vehicles but relies on the manufacturers to provide good data from their own internal qualification and testing. If data is suspect and/or the EPA finds it to be in err after its own qualification tests, the manufacturer will be forced to do a recall of said automobile for an emissions fix. If it were a gross error like not meeting the minimum Tier-II Bin 5 specs after 2007 as an example, the EPA could order the manufacturer to remove the automobile off the market! If you are receiving less then the EPA on this test or commuting in such a manner that you do not achieve the FTP75 results (cold starts below 20 degrees C as an example), your emissions can be far higher. There is no if or maybe, they just are. Since the Prius II is ICE off ~ 45 - 50% of the time in the FTP75 tests, the Prius II is the automobile receiving the free ride, not any other.
___Tsk, tsk, tsk. If you aren’t hitting the EPA city numbers, your emissions are even worse then what Toyota will guarantees to the EPA that your Prius II will emit after 100 - 120,000 miles! Remember, the Emissions are based off the FTP75 test. The average HCH appears to be hitting their numbers but the Prius II is falling short by a rather large percentage unfortunately. ___I do not need to guess. As you know, I did not mention the lean-burn HCH but I did mention the PZEV based HCH and you can purchase that in a 5-speed with 45/51 mpg city/highway EPA estimates. The Lean-Burn capable LEV-II rated HCH receives an EPA city/highway estimate of 46/51. With the non-hybrid PZEV based Accord, you lose nothing in the way of HP/Torque or FE in the city or highway per the EPA estimates.

___Anything else?

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

Who gets a free ride ?
I understand your argument, that ICE-on pollutes more than ICE-off, and to the extent that real-world driving has more ICE-on, there is more pollution during that duration. This makes sense as far as it goes, but you ignore the emission profile differences during the ICE-on phases and transitions, and so to my mind jump to a conclusion that is not warranted. Consider this data on the Prius I, from the NREL (also posted in the share section):

Test..........Temp..........CO........Nox......... HC.........MPG
FTP75..........69.9.........0.095.....0.008......0 .007......54.7
HWFET.........72.7.........0.168.....0.002......0. 002......54.9

Similar MPG in both tests, but huge differences *either way* depending on the pollutant measured.

So, I think that emissions during the drive cycle in the Prius is a complex beast, and cannot simply be reduced to what percentage of the time the ICE is off. What can be said with some confidence, however, is my point from before: During STOP in city driving, the Prius (and any hybrid that shuts the ICE off) is not emitting pollutants. Since this is a given part of city driving that is not part of FTP75 as far as I know (sitting at multiple signals for 30 - 60 seconds), this difference is not being measured, to the ICE only car's benefit. If I'm wrong about the test format, I retract my free-ride contention. Otherwise, it stands.

Different HCH versions
OK, I am confused. Does a model exist that lean burns, AND has the MAF and CAT you mentioned earlier all in one package ?

 

Hi EricGo:

___With the above, consider the differences between the FTP75 and the HWFET. It is the cold start in the FTP75 (at least a 12 hour off cold soak, start, and immediately run the FTP75 cycle in 20 - 30 degrees C ambient) that creams ones emissions in whatever you drive. The problem as I see it is that most of us do not have the year round luxury of a cold start at 20 - 30 degrees C so we have even worse emissions! 70 - 80% of the NOx emitted comes from the first second after you turn the key to the first transition from accel to decel before the CAT is truly lit off. This is why you see such high NOx and CO in the FTP75 vs. the warmed up soak method used in the HWFET.

___I am not that familiar with the CARB LA92 tests but I know they run higher speeds with less off/idle time. Maybe you can provide details on this one?

___I do not understand what you are saying “stands or not”? The FTP75 has plenty of stopped and idle time built into it to mimic a city start/stop cycle?

___The lean-burn capable HCH ICE is the LEV-II rated one, not the PZEV rated one from my understanding? I have never seen the details other then what has been posted by us uneducated - back yard mechanic type - “experts” in various hybrid forums around the net I am sure the details are posted over at Honda News just as they are for the non-hybrid Accord PZEV but I have never looked it up.

___Good Luck

___Wayne R. Gerdes
___Waynegerdes@earthlink.net

 

WOW, lots' of interesting data, interpretations, ideas, thoughts.

Cool, and I've learned a lot already (at the very least how little I know)!
Thanks guys!

Here are a few more thoughts:
The point about cold starts is interesting, but AFAIK the Prius should do better than others in real life because of the coolant thermos (depending on how long it was off)?

Also, in terms of real mileage database, and comparisons between different cars:
The RMDB is great, but one of the difficulties in comparing data across vehicle types is that the databases for different vehicle types have more differences than the vehicles: individuals who drive them and their needs and habits. There are reasons why some buy a HCH, some a Prius and some an Insight. I bought a Prius because a two seater is too small for me, and I need a htachback for getting my bike(s) inside the car. What I'm saying is: I think there is a given chance that Prius owners have their cars more loaded up than Insight owners or even HCH owners, with passengers and/or loads (at least on average). This would skew results from the RMDB: if all Prius owners would switch to HCHs, I'm speculating the avg mileage for HCHs would drop, because on average people might drive with a greater load (same would apply to Insights if you could even fit that many people or that much gear). Likewise, if all Insight drivers would switch to Prii, Prius avgs would go up (summat) because they would drive with fewer occupants or less load. Also, maybe people who have longer trips (and thus fewer of the mileage killing short trips) are more inclined to buy Insights? So, this just as a caveat in terms of comparing vehicles and their pollution, based on both/either EPA values and /or combined with RMDB.
In that respect I think it would be great of EPA mileage and smog testing procedures would be revised, and maybe would include more than just city and hwy. Maybe have several city ratings, based on short vs longer trips, winter vs summer, etc..

 

lakedude, what about the (2006) HCH that will be out (I-THINK) in the fall that is suppose to be with higher output and better FE? I guess the question is compared to the Prius, of course that is assuming the 06 HCH has those new standards and the current Prius already does.

BTW, on the news tonight the goverment is looking into the reported condition of the Prius having problems cutting off at speeds around 30-35 MPH for (NO-REASON). Apparently this condition is being reported to Toyota Dealers by more than a few owners.

terry