UW-Madison Hybrid Vehicle Team working with Engine Research Center to apply dual-fuel RCCI engines in series and parallel hybrids
23 July 2011
The University of Wisconsin-Madison Hybrid Vehicle Team will work with the UW-Madison Engine Research Center to test implementations of Reactivity Controlled Compression Ignition (RCCI) engines being developed by UW mechanical engineering professor Rolf Reitz and his colleagues.
RCCI is a dual-fuel compression-ignition engine low-temperature combustion (LTC) strategy that uses in-cylinder fuel blending with at least two fuels of different reactivity (e.g., diesel and gasoline) and multiple injections to control in-cylinder fuel reactivity to optimize combustion phasing, duration and magnitude. RCCI results in efficient, premixed-charge combustion with near zero levels of NOx and soot. (Earlier post.)
Earlier this year, Reitz presented work showing that, with only small changes in injection parameters, the efficient and low-emission combustion characteristics of a heavy-duty engine using RCCI can be adequately reproduced in a light-duty engine. Reitz’s team has modeled a 53% gross indicated efficiency for the improved light-duty engine.
Glenn Bower, a mechanical engineering faculty associate and UW vehicle team advisor, estimates that using RCCI, the team vehicles will emit 75% fewer greenhouse gases, surpassing the 2010 vehicle emission standards with minimal aftertreatment.
Fundamentally you can’t get too much better than this. You can’t eliminate friction, but we’re getting pretty close to the maximum amount of mechanical energy we can get from breaking a chemical bond.
—Glenn Bower
Bower’s team will use ethanol instead of gasoline, and biodiesel instead of standard diesel.
The team is converting two of its former competition vehicles for this purpose. The first, a Saturn Vue called the eMOOve, will be a series hybrid, to be completed in 2012. By 2013, the team will also convert its Chevy Equinox, called MOOVADA, to be a parallel hybrid, in which the battery and the engine work together. This will take more work because the engine must operate smoothly at about 1,000 different engine speeds and loads, Bower says.
Rolf Reitz’s graduate student team is hectically converting and calibrating engines for RCCI. As the engines become available, the undergraduates in the Hybrid Vehicle Team will integrate them into functioning hybrid vehicles.
—Glenn Bower
Bower says he hopes incorporating the RCCI engine technology into a vehicle will encourage industry leaders to adapt it for vehicles and even stationary power generators.
One hurdle, though, will be the fuel infrastructure. In order to fuel an RCCI engine, a gas station pump must be able to dispense both gasoline or ethanol, and diesel or biodiesel, simultaneously.
We always have to battle fuel infrastructure. But we do have diesel fuel and we usually have ethanol that’s fairly readily available. The idea of basically having a pump with dual nozzles filling both tanks simultaneously isn’t out of the question, because they already have the tanks.
—Glenn Bower
The MOOVADA, which is currently running as a parallel hybrid with an ethanol engine, will be on display this weekend at the Green Drive Expo, part of the Dane County (Wisconsin) Fair. On 10 Aug., the hybrid vehicle team also will showcase MOOVADA at UW-Madison Day at the Wisconsin State Fair.
Why the requirement to fill both tanks simultaneously?
Posted by: Nick Lyons | 23 July 2011 at 11:16 AM
Of course filling both tanks simultaneously is NOT an issue.
But if we pretend it IS, then we pretend/assume this technology is around the corner.
It isn't - because it isn't.
But this is quite possibly excellent work; they deserve acknowledgment and acclaim.
Oh, never mind, they are handling that themselves.
Posted by: ToppaTom | 23 July 2011 at 05:45 PM
Both methods: RCCI of University of Wisconsin and PPC of Lund University seem promising to bring Indicated Thermal efficiency to 57-59%.
The PPC method uses only US unleaded gasoline injection.
The RCCI method requires both gasoline and diesel fuel, at 80% gasoline and 20% diesel fuel.
However, another research has shown that gasoline mixed with 1.75% of DTBP, a cetane enhancer, can raise the gasoline mixture's cetane rating enough to substitute for diesel fuel. So, 1.75% x 20% = 0.35% DTBP vs gasoline by weight. With such a low percentage of DTBP used, a car will need only to refill the DTBP storage tank perhaps only as infrequently as every oil change interval. This on the ball park with refilling the urea container in SCR-equipped diesels. Perhaps doable, to really boost the efficiency of diesel-type ICE, with significant improvement in post-combustion exhaust emission, allowing practical adaptation to the passenger LDV fleets.
By contrast, the expensive diesel exhaust treatments like SCR and DPF have significantly limited the market penetration of Light diesel vehicles.
Posted by: Roger Pham | 23 July 2011 at 05:47 PM
Clarification: the 57-59% Indicated Thermal Efficiency improvement mentioned above is for heavy-duty diesels. For light-diesel engines, the improvement will be in order of 50-53%. Still very good!
Posted by: Roger Pham | 23 July 2011 at 05:51 PM
If the baseline vehicle was something like a Chevy Volt, using electric power for 80% of mileage and liquid fuels for 20%, designing for exotic liquids might be reasonable. Chevy Equinox? I laugh.
Posted by: Engineer-Poet | 24 July 2011 at 08:17 PM
if the goal is efficiency, hard to beat a diesel-electric hybrid.. without having two manage two fuel tanks in the car.
Pham's DTBP solution sounds more practical and affordable.
SCR equipped VW Passat is coming to the US, so the urea fluid will become commonplace.
Posted by: Herm | 29 July 2011 at 07:09 AM