Quote:
Originally Posted by WesternStarSCR
Dave,
Do you think Mazda is mostly treating the regen cycle like that of the pre DEF (EPA 07) trucks prior to EPA 10 (just using rich fuel and heat since they do not use DEF)?
I wonder if regen cycle is included in EPA test cycle numbers for FE or not.
I know it was a big deal when Detroit Diesel got their FE back up in 2010 and 2013, after the EPA 07 hit they took for having to run high temp regens.
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The FE increase of the SCR engines had little to do with regen cycles. EPA07-09 require in-cylinder NOx control, using ridiculous amounts of EGR and retarded timing, causing poor efficiency. Because EPA10+ engines take care of most NOx with aftertreatment (SCR), EGR flow can be reduced and timing/fuelling tuned for much better FE. Regen cycles did not change a whole lot for EPA10.
Aftertreatment fuel usage in the Cruze will depend largely on duty cycle. Low load city driving will require more aftertreatment fuel. Mostly highway usage will require much less aftertreatment fuel because of naturally higher engine out exh temps.
Typically in on-highway truck applications, overall aftertreatment fuel usage is only a couple percent of total fuel usage.