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New Cummins Medium Duty Truck Engine Tuned for E85

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  Another powerplant choice for truck manufacturers.  This is always good.  I live in a rural area and

 

 watch farm equipment roll by on the county road each day.  It would be good to see some of these be

 

 ethanol powered -- to "close the loop" on renewable fuel generation/use.  Not as many trucks going by

 

as tractors / combine/ other implements -- but at harvest time,  lots of trucks loaded with beets , headed to

 

 the processing pile.  These trucks have heavy torque needs,  and are rolling constantly during the harvest

 

campaign.  Same can be said for support equipment for wheat, corn,  sorghum , as trucks make their way into

 

and out of the fields 24/7 , until end of campaign.   Plenty of E85 fuel available here. too. 

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Diesel efficiency is suffering per technology to control NOx emissions. Automotive diesel has adapted the lower cost approach of utilizing cooled EGR gas to limit NOx. They utilize an oxygen sensor, throttle plate, and electronic control of cooled exhaust gas to dilute and decrease high temps of exhaust. Up till now diesel had an unfair advantage per emissions as they had no requirement for oxygen sensor and stoichiometric balance of fuel. They could squirt diesel per desired Hp need, problem was they generated much NOx, but given a pass up till current day by EPA. Meanwhile ethanol suffered per SI engine requirement of absolute stoichometric balance of fuel via oxygen sensor detection of O2 in exhaust. This requirement was especially damaging to ethanol as the fuel carried liquid oxygen in which naturally decreased nitrogen percentage within combustion, thus lessening the need for strict exhaust O2  compliance. So, diesel either adapts very expensive exhaust treatment or lowers efficiency to meet Nox emission requirement as compared to ethanol increasing efficiency of the SI engine and natural lower exhaust emission cost. Ethanol has no sulfur within it's pure fuel, but does contain nitrogen. How much the nitrogen content offsets the pure oxygen content per NOx production is unknown, but the optimized ethanol engine has much easier and low cost path to emissions control. Also, the ethanol fueled engine has better ability for NOx control per higher EGR dilution and cool lean burn technology. I would guess the nitrogen within ethanol could be processed or controlled like gasoline is now processed if it were to become a conformance problem. The ethanol optimized engine is looking good from all angles. The torque (max BMEP) as reported by the Cummins test comparison was 2.5x greater as compared to gasoline and Hp or power density 2.7x that of diesel. So, that could translate into, lets say a 500 cc Fiesta, 1L Fusion, or 1.5L Mustang and heavy duty pickup.

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The darling of powerful tools to meet Environmental concerns lies directly on the path of optimized E85 engine. Nothing comes close to cellulosic ethanol fueled optimized engine. University of Toronto just published a life cycle analysis of natural gas fuel for automotive. They compared a conventional unleaded vehicle CV to NG. Emissions of the CV vehicle running on natural gas decreased 10-20% as compared to CV running on unleaded. A hybrid CNG CV vehicle decreased emissions 30% and this was comparable to BEV recharged by the grid with the typical natural gas power plant. Problem with the BEV was the vehicle was 30% more expensive to own. So, the Toronto analysis summary was CNG HEV the sweet spot and the only advantage to BEV was to displace pollution away from urban areas. When one throws in the mix the optimized E85 engine rating of decreasing GHG emissions 85% per California standards of the Cummins medium duty van study, game over. Think of the advantage of ethanol engine almost zero particulate rating vs diesel's  unhealthy micro carbon particle tailpipe emission. Diesel's expensive SCR pollution equipment to control NOx, is not needed with ethanol. NOx is a factor of nitrogen within intake air and high combustion temperature. While ethanol does have high combustion temperature the engine doesn't require as much intake air per the fuel oxygen content and hence naturally less nitrogen to create NOx. This particular character of ethanol, also, allows engine to achieve better control of NOX control per recirculate of cooled exhaust gas. Actually, exhaust gas can serve two purposed within the engine. Upon cold engine start up, the valve timing can be adjusted to increase hot exhaust within combustion chamber. This will heat intake air, decrease excessive fuel, and eliminate much of the cold start emission problem. Properly tuned spark plugs and ignition that does not need to be tuned to unleaded fuel also a big help. 

Secondly, cooled exhaust gas dilution within intake air can mitigate high temperature combustion temps upon high horsepower need. It would act to trim and control excessive power and heat that would produce NOx. Cooling turbo air, also, very productive for both power and control of NOx. Utilizing exhaust gas to trim unneeded fuel is a great mileage trick. Current, FFV technology will squirt ethanol per oxygen sensor demand. This is wasteful, especially with ethanol that carries liquid oxygen on board, but a requirement of low tail pipe emissions. An optimized ethanol engine would recirculate the exhaust to trim oxygen within combustion chamber to exact need of vehicle and driver. The oxygen sensor should always be in balance and not demand over supply of fuel to decrease oxygen level in exhaust. They have similar technology within the natural gas turbine for power plant called DLN. Basically, they utilize a low temperature pre burner to minimize oversupply of oxygen.

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BTW, Shell and other gasoline suppliers advertise quality premium fuel that contains nitrogen. They do this per need to clean up fossil fuel soot and gunk deposits problem as their premium product contains no ethanol. But, adding nitrogen will produce more NOx tailpipe emissions. Better to utilize ethanol for the task as it's a cheaper component and offers benefit to lower carbon emission and lessening of the unhealthy petrol components that raise RVP and octane.  

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