a honda that ws banned?

[mkiVX]

ok gassavers..
A while back i say a good 5-6 years ago
i was reading on line about the vx and what not and i came across an article explaining the reasons why the vx was canned and also explaining that the civic hx was not as good.. I also read that there was supposed to be a civic that was going tp replace the vx that would get 60mpg plus.the government
supposedly did not allow it to to come to the states and honda never made it and opted to go with the hx instead
i read this somewhere a while ago. it was supposed to be the civic zx or something like that...


can anybody back me up on this.


thanks

[samandw]

My understanding, from something I read years ago on the internet, in 1996 the gov mandated 14.6:1 air:fuel mixture, effectively eliminating lean-burn technology. I read it on the internet though, so take it with a rather large truck-load of salt. Also the Insight is KNOWN to have lean-burn capability, but being a hybrid maybe it can get away with it? You might want to see if the NOX regs changed in 1996. . .Excessive NOX emissions is the real challenge with lean-burn technology. Never heard of the ZX though. . .

[cfg83]

samandw -

Originally Posted by samandw

My understanding, from something I read years ago on the internet, in 1996 the gov mandated 14.6:1 air:fuel mixture, effectively eliminating lean-burn technology. I read it on the internet though, so take it with a rather large truck-load of salt. Also the Insight is KNOWN to have lean-burn capability, but being a hybrid maybe it can get away with it? You might want to see if the NOX regs changed in 1996. . .Excessive NOX emissions is the real challenge with lean-burn technology. Never heard of the ZX though. . .

The California VX had lower MPG ratings than the non-California VX's because it was reguired to meet more stringent California NOx emissions standards. Soooooooo, it makes sense that the standard would be getting tighter, also leading to lower MPG figures. I am pretty sure that the HX also has lean-burn tech.

CarloSW2

[SD26]

Originally Posted by samandw

You might want to see if the NOX regs changed in 1996. . .Excessive NOX emissions is the real challenge with lean-burn technology. Never heard of the ZX though. . .

That actually sounds good.

I know that the EPA required Ford to make changes to the Power Stroke Diesel in 1996 for NOX.

[RoadWarrior]

I think the problem with lean burn the way honda did it was not that it produced more NOx than a regular motor, because they used a kind of stratified charge approach, but that it didn't have enough hydrocarbons spewing out for the cat to reduce NOx further. Cat needs something to do with the O2 it yanks away from the N, so it needs unburned HC to make H2O and CO2 with. (Yeah I know in a perfect world it should just release O2, but it's "stuck" to the cat and needs something energetic to yank it off again)

[suspendedhatch]

The HX actually improved on lean burn technology via the use of a crank angle sensor that allows the ECU to "push" it as lean as it can and then sense when it's too lean and back it off.

The increased presence of oxygen combined with higher combustion temps lead to higher incidence of NOx, but there is nothing stopping you from cooling down the combustion process.

[Lug_Nut]

Originally Posted by RoadWarrior

I think the problem with lean burn the way honda did it was not that it produced more NOx than a regular motor, because they used a kind of stratified charge approach, but that it didn't have enough hydrocarbons spewing out for the cat to reduce NOx further. Cat needs something to do with the O2 it yanks away from the N, so it needs unburned HC to make H2O and CO2 with. (Yeah I know in a perfect world it should just release O2, but it's "stuck" to the cat and needs something energetic to yank it off again)

The 1996 VW TDI diesel (as high as 100:1 air/fuel at idle) suffered from this same lack of post engine fuel to work in the cat. It had an added fifth injector spitting raw fuel into the cat based on a pair of temperature sensors, one before, one after the cat just to provide the cat with needed fuel. If the front sensor was hot enough to ignite, but the rear one was cold indicating low cat conversion, the fuel was spritzed in.
Or so it was supposed to work.
It worked well enough to get the new engines certified for 50 state sale, but in practice was a smoky, fuel consuming mess. The remedy was a new computer that kept this supplemental injector turned off, new injectors that opened at 3,000 psi instead of 2,750, and a delay of the onset of injection to drop peak combustion temperatures, all for lower NOx.
The device was discontinued for the 1997 model year TDI, but now has returned in a much improved form for the 50 state approved 2009 "Clean Diesel" Jetta TDI.
Time will tell if it keeps working better than the 1996 predecessor (from the Latin for already dead!)

[aalb1]

On the same Honda note... the B18b engines that are found in the 94-01 Integra LS made a change with their PCV system from 96 on. Honda took away the Charcoal canister for stricter emissions purposes. The GSR engines kept these canisters because only a certain % of the cars on the Acura line up needed to improve.

Though they ditched the VX, I wonder what other cars in the Honda line up changed from an emissions perspective.