Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com - View Single Post

ever_green · 03-31-2015, 02:16 PM

I know I don't have a honda but I have been able to experiment with fairly lean mixtures of 1.3 lambda at higher RPMs which equate to 65-80 mph cruising with my Subaru (higher RPM because intake velocity is faster and the fuel atomizes properly in manifold). I haven't had any misfire issues. This is with EGR. The reason I can't go any leaner is because my wideband is restricted to 0.7-1.3 lambda and timing is already maxed out at 54* BTDC.

In any case other than larger than normal throttle opening during cruise I haven't really observed any noticeable gains in mileage. I know bosch research indicates that 15.6-16.8 AFR produces best BSFC but I don't want to go that rich because of extreme NOx emissions there. Even so I ended up reverting back to more normal 1.0 Lambda mixtures and enjoyed the better throttle response and cooler cylinder head temps (though hotter exhaust temp). Yeah the new stratified charge lean burn Hondas might help, but the new Prius can get pretty good mileage on highway without lean burn. Therefore I personally don't see the point. I mean the cost of new lean burn catalysts are staggering from what I have heard and I'm not sure Honda owners will be pleased when it comes to its service/replacement time.

03-31-2015, 02:16 PM	#98 (permalink)
ever_green Master EcoModder Join Date: May 2011 Location: Toronto Posts: 264 gueff - '19 Mercedes Benz A250 4MATIC AMG 90 day: 30.55 mpg (US) Thanks: 8 Thanked 79 Times in 33 Posts	I know I don't have a honda but I have been able to experiment with fairly lean mixtures of 1.3 lambda at higher RPMs which equate to 65-80 mph cruising with my Subaru (higher RPM because intake velocity is faster and the fuel atomizes properly in manifold). I haven't had any misfire issues. This is with EGR. The reason I can't go any leaner is because my wideband is restricted to 0.7-1.3 lambda and timing is already maxed out at 54* BTDC. In any case other than larger than normal throttle opening during cruise I haven't really observed any noticeable gains in mileage. I know bosch research indicates that 15.6-16.8 AFR produces best BSFC but I don't want to go that rich because of extreme NOx emissions there. Even so I ended up reverting back to more normal 1.0 Lambda mixtures and enjoyed the better throttle response and cooler cylinder head temps (though hotter exhaust temp). Yeah the new stratified charge lean burn Hondas might help, but the new Prius can get pretty good mileage on highway without lean burn. Therefore I personally don't see the point. I mean the cost of new lean burn catalysts are staggering from what I have heard and I'm not sure Honda owners will be pleased when it comes to its service/replacement time. Attached Thumbnails Last edited by ever_green; 03-31-2015 at 11:05 PM..