Quote:
Originally Posted by cRiPpLe_rOoStEr
I guess it would not be of much help.
Most likely non-methane hydrocarbons would increase, while NOx would eventually decrease, unless the ECM would trim down the stock fuel injection flow.
Had it been strictly to offset NOx, water injection would've been a more likely approach.
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The idea I'm taking about using the EGR is to add both propane and air through there. The goal is to trick the ECU into burning the propane with enough oxygen so it actual does something other than enrich the fuel mixture. By adding propane and oxygen together through the EGR the ECU will continue to add enough air and gasoline in through the the normal means. Since the propane will burn with the extra air the O2 sensors should see pretty much the same amounts of O2 as if the engine weren't modified, as long as the propane and air metering are good enough of course. The MAP sensor should compare to the throttle position sensor and MAF sensor like it would without the mod. The benefit would be it would burn the propane and make more power which would allow you to close the throttle more and use less gasoline over all.
But with fuel and air entering through the EGR valve NOx will increase since the A/F mix will be stoichiometric with no inert gas like to exhaust gas to lower the combustion temps.
Another con would be the throttle would tend to be more closed causing more pumping losses.