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1outlaw

This Will Be An Interesting Study When Complete

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This is a study of FFV drivetrains to find best shift points/gearing to take advantage of E85's higher torque/hp- the intent will be to improve mpg on E85 from what I understand- plus it appears to deal with some other optimizations such as valve timing events;

 

 

 

Development of a Flex Fuel Vehicle: Impact on Powertrain's Design and Calibration

 

Date Published: 2010-10-25Paper Number: 2010-01-2087

DOI: 10.4271/2010-01-2087

 

 

 

Author(s):

 

Adrien Halle - IFP

Alexandre Pagot - IFP

 

Abstract

 

The benefits of running on ethanol blended fuels are well known, especially global CO 2 reduction and performances increase. But using ethanol as a fuel is not drawbacks free. Cold start ability and vehicle autonomy are appreciably reduced. These two drawbacks have been tackled recently by IFP and its partners VALEO and Cristal Union. This article will focus on the second one, as IFP had the responsibility to design the powertrain of a fully flex fuel vehicle (from 0 to 100% of ethanol) with two main targets : reduce the fuel consumption of the vehicle and maintain (at least) the vehicle performances. Using a MPI scavenging in-house concept together with turbo charging, as well as choosing the appropriate compression ratio, IFP managed to reach the goals. Thanks to the adaptation of the inlet manifold, the intake camshaft as well as the piston and con-rod coupling, the 2L engine with a compression ratio of 10.5 delivers with RON 95 unleaded fuel a maximum torque of 290Nm constant between 2000rpm and 3500rpm, and 142kW at 5500rpm. But the output reaches with ethanol blended fuels 350Nm between 2000rpm and 3500rpm, and 150kW at 5500rpm, this from 20% to 100% of ethanol. Such performances made it possible to change the gearbox ratios in order to reduce the fuel consumption. The combination of intake camshaft design, variable valve timing and increased compression ratio also improves engine efficiency at part load. Compared to the standard engine, the BSFC's improvement reaches 7% at 2000rpm and 2bar BMEP. The complete adapted powertrain and engine control unit are now mounted in a vehicle and the calibration task is taking place, on the basis of test bench results. Vehicle results should be available for the coming autumn.

 

 

File Size: 4140K

 

 

 

Product Status: In Stock

See papers presented at SAE 2010 Powertrains Fuels & Lubricants Meeting, October 2010, San Diego, CA, USA, Session: Fuel & Additive Effects on SI Engine Performance (Part 1 of 2)

 

 

 

 

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wow... I feel like a "Special Ed Student" in an "advanced physics class"... :-[ :o :-[ :-[ :-[

 

while most of that went over my head... I do get the basic idea of their study...

 

It would be nice if a FFV could be able to adjust the timing and the gear shifting to better optimize the different fuel...

 

Though there would still be idiots bleeting on about the "30% fewer BTU's" BS...  ;) :laugh:

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Agreed, it will be interesting to see the outcome, but converting those numbers to something more familiar:

 

...the 2L engine with a compression ratio of 10.5 delivers with RON 95 unleaded fuel a maximum torque of 290Nm constant between 2000rpm and 3500rpm, and 142kW at 5500rpm. But the output reaches with ethanol blended fuels 350Nm between 2000rpm and 3500rpm, and 150kW at 5500rpm, ...

 

RON 95 = ~89 R+M/2?

 

142 kw = 190 hp

290Nm = 213 ft.lbs

 

 

Ethanol Blend

150 Kw = 200 hp

350 Nm = 258 ft.lbs

 

Not a terribly big improvement IMHO - especially when they mention a turbo involved.  But, I guess one big key is what exactly they mean by "...reduce the fuel consumption of the vehicle..."  If that is 'reduce consumption below what is was on gas, then that would not be too bad of a trade off.  But if they mean to just reduce it a few percent from what it was on ethanol, that shouldn't be hard at all.

 

I'm also a bit curious about"...this from 20% to 100% of ethanol.."  To me, it sounds like all the gains can be had from fuel as low as E20.  So it still seem like this is little more than a gas engine with a few tweaks and anything more than E20 is 'wasted' - unless the engine can adapt further.  I'd certainly think E85 - E98 would be able to give substantial power gains over E20 in an engine which can properly take advantage of the fuel.

 

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But using ethanol as a fuel is not drawbacks free.

 

1. Cold Start (how did they improve this?)

2. Autonomy (making a flexible engine to run two different fuel efficiently)

 

Using a MPI scavenging (some sort of tuned exhaust?)

Turbo charging

Appropriate compression ratio (per variable camshaft?) 

 

Thanks to the adaptation of the inlet manifold (is this cold start improvement?)

Intake camshaft as (converting to variable?)

Piston and con-rod coupling. (why? Strength?)

 

Such performances made it possible to change the gearbox ratios in order to reduce the fuel Consumption (torque went up 21% so gearing up 21% with ethanol? Also, must be variable when running gasoline)

 

Compared to the standard engine, the BSFC's improvement reaches 7% (probably a measure of improvement of ethanol as the engine optimized for gasoline, already. Meaning with an flexible engine more capable of exploiting ethanol advantage, 7% reduction. So the 25% mileage hit would decrease to 18%. By increasing drive ratio 21% they would be close to even.

 

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Though there would still be idiots bleeting on about the "30% fewer BTU's" BS...  ;) :laugh:

 

The reciprocating assembly for my ethanol engine is on its way, should be here next week. The goal of this particular engine is to show that BTUs dont mean as much in regards to a liquid fuel as people assume. :)

 

Trying to get an engine to run on both 100% gas and 100% ethanol is the problem, because gas wont work where ethanol works its best, but ethanol will work ok where gasoline does its best. Its not fault of ethanol that gas cant handle more compression and heat. :) Mine wont use anything less than E85, and really it wont live with pump gas at all.

 

I'll start a build thread on that engine when the parts arrive.

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Most guys in the performance world find a lot added torque down low with E85 as compared to gas. I am wondering if they are making gearing a part of that for thier study. If the cruise speed is also low enough in in rpm then the engine will "lug" a bit more and use the turbo just a bit- adding compression which E85 likes. I have not way of knowing if that is what they are thinking- but that is what I am 'tinkin" ;)

 

I too wondered what they were referring to with the 20-100% comment- BUT- a very nice study recently did show virtually no drop off in effective motor and research octane clear down to E50- could they be thinking it even goes lower? :-\

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Article does read the benefits of ethanol blend fuel for this fully flexed vehicle from 20% ethanol on up. So, engine design capable of exploiting ethanol at 20% concentration and no more? Meaning the physical constraints of engine and their design limited.

 

I'm guessing this is true as ethanol fueled engine efficiency really needs diesel strength. Ford ECCO boost that started upon evolution of ethanol fuel was beefed up, sized down, and received max boost with DI. This I believe a truly ethanol optimized engine would look like. Also, having a flex engine will incur a compromise cost such as not being able to be truly optimized for each fuel. This may not be a problem as the fuel supply is currently mixed with gasoline. But, hard to believe a 100% ethanol engine would look anything similar to 100% gasoline.

 

Lugging engine with manual gears a effective way to boost pressure. This the reason cold engines will run better under some load and not stall. Remember the shift indicator for economy? Ethanol with high torque ability should greatly improve mpg with tall gears. CVT trans may be just the ticket. Still would think an optimized ethanol engine would be low rpm, high pressure, high boost, low CI. They need a flex engine that would run h100 in summer and E85 in winter.

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