Onboard separation technology set to improve fuel economy

Posted: May 22, 2020 by oldbrew in Emissions, innovation, Travel
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Promotional video:

Regardless of questionable greenhouse climate theories, who wouldn’t want lower fuel consumption rates for their vehicle? ‘Up to 30%’ better economy is mentioned.
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A technology developed by researchers at the U.S. Department of Energy’s Pacific Northwest National Laboratory could pave the way for increased fuel economy and lower greenhouse gas emissions as part of an octane-on-demand fuel-delivery system, reports Phys.org.

Designed to work with a car’s existing fuel, the onboard separation technology is the first to use chemistry—not a physical membrane—to separate ethanol-blended gasoline into high- and low-octane fuel components.

An octane-on-demand system can then meter out the appropriate fuel mixture to the engine depending on the power required: lower octane for idling, higher octane for accelerating.

Studies have shown that octane-on-demand approaches can improve fuel economy by up to 30 percent and could help reduce greenhouse gas emissions by 20 percent.

But so far, the pervaporation membranes tested for octane on demand leave nearly 20 percent of the valuable high-octane fuel components in the gasoline.

In proof-of-concept testing with three different chemistries, PNNL’s patent-pending onboard separation technology separated 95 percent of the ethanol out of commercial gasoline. The materials are also effective for separating butanol, a promising high-octane renewable fuel component.

Market ripe for technology to improve fuel economy

High-compression engines that squeeze the most work out of each drop of fuel are the engines of the future. Unfortunately, these engines exacerbate a pesky problem known as engine knock.

Akin to a bicyclist whose feet slip off the pedals and slap around, knock happens when an engine’s piston and combustion sequence are momentarily out of sync—usually during acceleration. Knock can rob vehicles of power and even cause expensive engine damage.

Higher-octane fuels can eliminate knock but are expensive to produce. Ethanol is an inexpensive fuel additive that increases the octane rating to combat knock. The additive modestly curbs greenhouse gas emissions—but reduces vehicle performance and fuel economy.

When a car burns gas while sitting at a stop light or idling at the curb, it’s wasting the valuable high-octane fuel better used for acceleration.

That’s where PNNL’s onboard separation technology comes in. As part of an octane-on-demand system, the technology optimizes the available fuel by staging the right fuel for the right time.

Allan Tuan, a commercialization manager at PNNL, said that federal requirements for both renewable fuels and increasing fuel economy make new fuel strategies like octane on demand more important and more relevant than ever.

“With the increasing use of ethanol and, over time, other biofuels, a technology like PNNL’s onboard separation technology means we don’t need to choose between reduced greenhouse gas emissions and fuel economy,” said Tuan.

Full article here.

Comments
  1. Dave Ward says:

    Since the amount of high/low octane fuel needed for this new development is going to be dependent on individual driving styles, surely trying to separate it from a predetermined mixture is going to lead to a surplus, or lack of one or the other? If the idea is as good as they say, it might be better to have two separate tanks – in much the same way that most diesels have an “AdBlue” tank. I’m assuming that the high octane fuel would only be needed for fast driving and rapid acceleration, so a limited onboard supply might encourage the “Boy Racers” to stop behaving like prats.

    I admit that this approach would need an additional fuel distribution system, but hardly more stupid than trying to carpet the country with EV charging points…

  2. Peter Norman says:

    I remember doing brake load efficiency tests (at university long ago). Most ICE losses were through cooling and exhaust gas. Some of the latter can be recovered by a turbo-charger. For petrol engines the higher the compression ratio the higher the thermal efficiency. Yes, compression ratio is limited by pre-ignition but if you are going to vary the fuel type to fix this why not simply go diesel (about 30% more efficient). Or maybe we go gas turbine with light gas-oils. Use a small on-board one to provide EV power with cheapo batteries?
    Whatever happened to the 1960 Rover gas turbine project? Blast from the past. Check this:

  3. Peter Norman says:

    Sorry my link went to pieces. Just click YouTube playback to view.

  4. oldbrew says:

    The Jaguar turbine concept never took off.

    The micro gas turbines from Bladon Jets generate enough electricity to extend the range of the car to 900 km (559 miles) while producing 28 grams of CO2 per kilometre on the EU test cycle. While running solely on battery power, the C-X75 has an all-electric range of 110 km (68 miles).[10][11] Among other advantages, the micro turbines used in the C-X75 can be run on a range of fuels including diesel, biofuels, compressed natural gas and liquid petroleum gas.

    https://en.wikipedia.org/wiki/Jaguar_C-X75

  5. Peter Norman says:

    @Oldbrew. I seem to remember there were lots of scary zeros everywhere. Production numbers zero, sales forecast zero, C-X75 price tag was around £10e6 and the micro gas turbine ran up to 10e6 rpm!

  6. Curious George says:

    Do I understand the concept at all?
    1. States mandate the addition of alcohol to gasoline.
    2. This invention separates alcohol from gasoline, and improves fuel economy by 30%.

  7. JB says:

    Ye gods, but engineering perspicacity has become moribund!
    This is definitely the era of re-runs.

  8. Gamecock says:

    I’ll put it in the closet next to my 100-mpg carburetor.

    ‘Market ripe for technology to improve fuel economy’

    Wut? The market just COLLAPSED. Petrol pricing is the lowest in years!

  9. oldbrew says:

    ‘Up to’ always means ‘less than’ 😉

  10. ivan says:

    I can see one, or more, of the spiv types starting a backyard business using this to produce real petrol from the adulterated, government mandated fuel called petrol available today. If that caught on maybe the farmers could get back to growing food for people rather feeding the stupid ‘green dream’.

  11. Bloke down the pub says:

    ‘When a car burns gas while sitting at a stop light or idling at the curb, it’s wasting the valuable high-octane fuel better used for acceleration.
    My Mini has a stop-start system where it senses if you’re stopped and shuts the engine off. The engine restarts as soon as you put your foot on the accelerator again. I feel safe in saying their economy claims weren’t based on a comparison to this type of system, as there’d be less use for the low octane fraction of the fuel.
    BTW, with regards to gas turbine use in vehicles, I’ve heard that one reason they face bureaucratic obstacles is that they can use such a wide range of fuels. The govt beancounters were scared that everyone would be putting cheap, non-taxed fuels into them and they’d lose all their lovely revenue.

  12. oldbrew says:

    Bloke – they will lose all their fuel tax revenue anyway, plus the VAT on top, in an EV-only future.

  13. Stuart Brown says:

    OB – no. No they won’t. You can be sure of that. You just don’t know how exactly they will do it yet.

  14. stpaulchuck says:

    and the weight cost? and space? A vehicle is only as utile as the load it can carry and the price per mile/kilometer.

    A standard sedan like a Camry with 500 pounds of batteries and this separator, that leave a cargo capacity the size of a bowling ball and still only goes about 200 miles at the best of it, is NOT a good bargain. What will this add to the delivered price of the vehicle?

    It seems a two tank system of ethanol and real gasoline with a fuel flow/mixer controlled easily with today’s microcomputer technology and sensors would be a heck of a lot cheaper and more efficient. You could use fuel bladders in the single physical tank so a driver could ratio the fuel loads according to his experience. This would obviate the issue of different daily modes like a city driver and a country driver or expressway driver. The price for this would be small, improve performance and use current infrastructure.

    But then what do I know?

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